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Author Theuns, T.; Michel, K.H.
Title Free energy and structural phase transitions in mixed crystals: a microscopic derivation Type A1 Journal article
Year 1992 Publication Zeitschrift für Physik: B Abbreviated Journal
Volume 86 Issue Pages 125-131
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos A1992GV45100019 Publication Date 2005-03-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0722-3277;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 1 Open Access
Notes Approved no
Call Number (down) UA @ lucian @ c:irua:44748 Serial 1276
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Author Michel, K.H.; Nikolaev, A.V.; Verberck, B.
Title Theory of crystal structures of polymerized C60-fullerite and fullerides AC60, A=K, Rb, Cs Type H1 Book chapter
Year 2001 Publication Abbreviated Journal
Volume Issue Pages
Keywords H1 Book chapter; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication s.l. Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume 462-465 Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record;
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ lucian @ c:irua:36883 Serial 3614
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Author Nikolaev, A.V.; Michel, K.H.
Title Microscopic theory of quadrupolar oredring in TmTe Type A1 Journal article
Year 2001 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 63 Issue Pages 1-10
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000167402100025 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 7 Open Access
Notes Approved Most recent IF: 3.836; 2001 IF: NA
Call Number (down) UA @ lucian @ c:irua:36882 Serial 2033
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Author Nikolaev, A.V.; Michel, K.H.
Title Electronic structure and electric quadrupoles of a polymerized chain in solid AC60 Type A1 Journal article
Year 2001 Publication Solid state communications Abbreviated Journal Solid State Commun
Volume 117 Issue Pages 739-743
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000167538300010 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-1098; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.554 Times cited 10 Open Access
Notes Approved Most recent IF: 1.554; 2001 IF: 1.381
Call Number (down) UA @ lucian @ c:irua:36881 Serial 1009
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Author Michel, K.H.; Nikolaev, A.V.
Title Theory of distinct crystal structures of polymerized fullerides AC60, A=K, Rb, Cs: the specific role of alkalis Type A1 Journal article
Year 2000 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 85 Issue Pages 3197-3200
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000089807800033 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 16 Open Access
Notes Approved Most recent IF: 8.462; 2000 IF: 6.462
Call Number (down) UA @ lucian @ c:irua:34339 Serial 3615
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Author Nikolaev, A.V.; Michel, K.H.
Title Electric quadrupole interactions and the γ-α phase transition in Ce: the role of conduction electrons Type A1 Journal article
Year 2000 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
Volume 17 Issue Pages 15-32
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000089339900004 Publication Date 2003-05-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6028; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.461 Times cited 8 Open Access
Notes Approved Most recent IF: 1.461; 2000 IF: 2.077
Call Number (down) UA @ lucian @ c:irua:34338 Serial 888
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Author Zieliński, P.; Michel, K.H.
Title Microscopic model of surfaces in orientationally disordered ionic crystals : the (001) surface of KCN Type A1 Journal article
Year 1992 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 46 Issue 8 Pages 4806-4815
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The crystallographic structure and the distribution of orientations of molecular ions are studied near the surface in an orientationally disordered crystal with the use of a Green-function formalism. The orientational degrees of freedom are treated by means of symmetry-adapted functions of angular coordinates. The structure of the (001) surface of KCN in its cubic fcc phase is then predicted using the existing data on the interaction of the ions K+ and CN-. A local antiferroelectric and antiferroelastic order i shown to exist in the surface region. The magnitude of the order and the spatial extent of the ordered re ion increase as the temperature approaches the point of the phase transition to the ordered phase. The,influence of the external electric field on the structure of the surface is predicted.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1992JK72500049 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 4 Open Access
Notes Approved PHYSICS, CONDENSED MATTER 16/67 Q1 #
Call Number (down) UA @ lucian @ c:irua:2974 Serial 2029
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Author Michel, K.H.
Title Molecular structure and orientational ordering in solid C60 Type A1 Journal article
Year 1992 Publication The journal of chemical physics Abbreviated Journal J Chem Phys
Volume 97 Issue 7 Pages 5155-5162
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A microscopic theory, which describes the orientational dynamics of C60 molecules in the face-centered cubic phase of C60-fullerite, is formulated or the case of a complex molecular structure. Interaction centers which comprise atoms, double bonds, and single bonds as molecular constituents contribute to the intermolecular potential. Orientation dependent physical properties are described in terms of symmetry-adapted rotator functions. It is found that a same set of rotator functions is sufficient even in the case of a complex molecular structure. Phase transition temperatures are discussed for various models of molecular structure.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos A1992JR33800062 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9606; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.952 Times cited 20 Open Access
Notes Approved no
Call Number (down) UA @ lucian @ c:irua:2973 Serial 2185
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Author Michel, K.H.
Title Sequence of orientational phase transitions in solid C60 Type A1 Journal article
Year 1992 Publication Chemical physics letters Abbreviated Journal Chem Phys Lett
Volume 193 Issue Pages 478-480
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1992HZ32900006 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0009-2614; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.897 Times cited 14 Open Access
Notes Approved MATERIALS SCIENCE, MULTIDISCIPLINARY 96/271 Q2 #
Call Number (down) UA @ lucian @ c:irua:2971 Serial 2985
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Author Michel, K.H.
Title Free energy and orientational phase transition in solid C60 Type A1 Journal article
Year 1992 Publication Zeitschrift für Physik: B Abbreviated Journal
Volume 88 Issue Pages 71-78
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos A1992JB10700009 Publication Date 2005-04-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0722-3277;1434-6036; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 33 Open Access
Notes Approved no
Call Number (down) UA @ lucian @ c:irua:2967 Serial 1275
Permanent link to this record
 

 
Author Nikolaev, A.V.; Michel, K.H.; Copley, J.R.D.
Title Orientational disorder and order in C60-fullerite and in MC60-alkali metal fullerides Type H3 Book chapter
Year 1999 Publication Abbreviated Journal
Volume Issue Pages 183-214
Keywords H3 Book chapter; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Plenum Press Place of Publication New York Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ lucian @ c:irua:28505 Serial 2515
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Author Nikolaev, A.V.; Michel, K.H.
Title Quantum charge density fluctuations and the γ-α phase transition in Ce Type A1 Journal article
Year 1999 Publication European physical journal : B : condensed matter and complex systems Abbreviated Journal Eur Phys J B
Volume 9 Issue Pages 619-634
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000081615500009 Publication Date 2002-08-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6028; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.461 Times cited 19 Open Access
Notes Approved Most recent IF: 1.461; 1999 IF: 1.705
Call Number (down) UA @ lucian @ c:irua:28504 Serial 2774
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Author Lamoen, D.; Michel, K.H.
Title Coupling of orientational and translational modes in solid C60 and C70 Type A1 Journal article
Year 1999 Publication Phase transitions Abbreviated Journal Phase Transit
Volume 67 Issue Pages 789
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York Editor
Language Wos 000079806300017 Publication Date 2007-07-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0141-1594;1029-0338; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.06 Times cited 2 Open Access
Notes Approved Most recent IF: 1.06; 1999 IF: 0.622
Call Number (down) UA @ lucian @ c:irua:27830 Serial 537
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Author Bussmann-Holder, A.; Michel, K.H.
Title Bond geometry and phase transition mechanism of H-bonded ferroelectricity Type A1 Journal article
Year 1998 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 80 Issue Pages 2173-2176
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000072385400037 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007;1079-7114; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 8.462 Times cited 81 Open Access
Notes Approved Most recent IF: 8.462; 1998 IF: 6.017
Call Number (down) UA @ lucian @ c:irua:23987 Serial 246
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Author Nikolaev, A.V.; Prassides, K.; Michel, K.H.
Title Charge transfer and polymer phases in AC60 (A=K, Rb, Cs) fullerides Type A1 Journal article
Year 1998 Publication The journal of chemical physics Abbreviated Journal J Chem Phys
Volume 108 Issue Pages 4912-4923
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000072588400025 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9606; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.965 Times cited 14 Open Access
Notes Approved Most recent IF: 2.965; 1998 IF: 3.147
Call Number (down) UA @ lucian @ c:irua:23985 Serial 338
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Author Nikolaev, A.V.; Prassides, K.; Michel, K.H.
Title Phase transitions in AC60 (A=Rb, Cs) fullerides Type A3 Journal article
Year 1997 Publication Recent advances in the chemistry and physics of fullerenes and related materials Abbreviated Journal
Volume 5 Issue Pages 450-460
Keywords A3 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ lucian @ c:irua:21182 Serial 2596
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Author Michel, K.H.; Copley, J.R.D.
Title Orientational mode coupling, diffuse scattering, and the order-disorder phase transition in solid C60 Type A3 Journal article
Year 1997 Publication Zeitschrift für Physik: B: condensed matter and quanta Abbreviated Journal
Volume 103 Issue Pages 369-376
Keywords A3 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos A1997XL52100005 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0340-224x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 21 Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ lucian @ c:irua:21181 Serial 2517
Permanent link to this record
 

 
Author Michel, K.H.; Copley, J.R.D.
Title Orientation fluctuations, diffuse scattering and orientational order in solid C60 Type H3 Book chapter
Year 1996 Publication Abbreviated Journal
Volume Issue Pages 381-384
Keywords H3 Book chapter; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher World Scientific Place of Publication Singapore Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved COMPUTER SCIENCE, INTERDISCIPLINARY 11/104 Q1 # PHYSICS, MATHEMATICAL 1/53 Q1 #
Call Number (down) UA @ lucian @ c:irua:16358 Serial 2512
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Author Nikolaev, A.V.; Michel, K.H.
Title Microscopic theory of the rhombohedral phase and transition to the monoclinic phase of solid C70 Type A1 Journal article
Year 1996 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 54 Issue 18 Pages 12733-12743
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Starting from a model of microscopic interactions between C-70 molecules, we have developed a theory which describes the orientational dynamics and its coupling to lattice displacements in the rhombohedral phase of C-70 fullerite. The Landau free energy is calculated. We obtain a first-order phase transition to a monoclinic structure with the space group P2(1)/m. The transition is driven by the condensation of orientational quadrupoles at the F point of the Brillouin zone of the rhombohedral lattice. We find no evidence that the monoclinic structure is connected with the freezing in of orientations around the fivefold molecular axis. We calculate the lattice strains that are associated with the transition to the monoclinic structure. The theory is compared with a range of experimental data on the phase transition.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1996VT68200028 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 5 Open Access
Notes Approved no
Call Number (down) UA @ lucian @ c:irua:16357 Serial 2034
Permanent link to this record
 

 
Author Michel, K.H.; Scuracchio, P.; Peeters, F.M.
Title Sound waves and flexural mode dynamics in two-dimensional crystals Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue 9 Pages 094302
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Starting from a Hamiltonian with anharmonic coupling between in-plane acoustic displacements and outof-plane (flexural) modes, we derived coupled equations of motion for in-plane displacements correlations and flexural mode density fluctuations. Linear response theory and time-dependent thermal Green's functions techniques are applied in order to obtain different response functions. As external perturbations we allow for stresses and thermal heat sources. The displacement correlations are described by a Dyson equation where the flexural density distribution enters as an additional perturbation. The flexural density distribution satisfies a kinetic equation where the in-plane lattice displacements act as a perturbation. In the hydrodynamic limit this system of coupled equations is at the basis of a unified description of elastic and thermal phenomena, such as isothermal versus adiabatic sound motion and thermal conductivity versus second sound. The general theory is formulated in view of application to graphene, two-dimensional h-BN, and 2H-transition metal dichalcogenides and oxides.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000409246200003 Publication Date 2017-09-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 6 Open Access
Notes ; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program. ; Approved Most recent IF: 3.836
Call Number (down) UA @ lucian @ c:irua:145630 Serial 4751
Permanent link to this record
 

 
Author Michel, K.H.; Çakir, D.; Sevik, C.; Peeters, F.M.
Title Piezoelectricity in two-dimensional materials : comparative study between lattice dynamics and ab initio calculations Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 95 Issue 95 Pages 125415
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The elastic constant C-11 and piezoelectric stress constant e(1),(11) of two-dimensional (2D) dielectric materials comprising h-BN, 2H-MoS2, and other transition-metal dichalcogenides and dioxides are calculated using lattice dynamical theory. The results are compared with corresponding quantities obtained with ab initio calculations. We identify the difference between clamped-ion and relaxed-ion contributions with the dependence on inner strains which are due to the relative displacements of the ions in the unit cell. Lattice dynamics allows us to express the inner-strain contributions in terms of microscopic quantities such as effective ionic charges and optoacoustical couplings, which allows us to clarify differences in the piezoelectric behavior between h-BN and MoS2. Trends in the different microscopic quantities as functions of atomic composition are discussed.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000396013400005 Publication Date 2017-03-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 29 Open Access
Notes ; The authors acknowledge useful discussions with L. Wirtz and A. Molina-Sanchez. This work was supported by the Methusalem program and the Fonds voor Wetenschappelijk Onderzoek-Vlaanderen. Computational resources were provided by HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. ; Approved Most recent IF: 3.836
Call Number (down) UA @ lucian @ c:irua:142444 Serial 4603
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Author Michel, K.H.; Neek-Amal, M.; Peeters, F.M.
Title Static flexural modes and piezoelectricity in 2D and layered crystals Type A1 Journal article
Year 2016 Publication Physica status solidi: B: basic research Abbreviated Journal Phys Status Solidi B
Volume 253 Issue 253 Pages 2311-2315
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Piezo- and flexoelectricity are manifestations of electromechanical coupling in solids with potential applications in nanoscale materials. Naumov etal. [Phys. Rev. Lett. 102, 217601 (2009)] have shown by first principles calculations that a monolayer BN sheet becomes macroscopically polarized in-plane when in a corrugated state. Here, we investigate the interplay of layer corrugation and in-plane polarization by atomistic lattice dynamics. We treat the coupling between static flexural modes and in-plane atomic ion displacements as an anharmonic effect, similar to the membrane effect that is at the origin of negative thermal expansion in layered crystals. We have derived analytical expressions for the corrugation-induced static in-plane strains and the optical displacements with the resulting polarization response functions. Beyond h-BN, the theory applies to transition metal dichalcogenides and dioxides. Numerical calculations show that the effects are considerably stronger for 2D h-BN than for 2H-MoS2.
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000390339000002 Publication Date 2016-10-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1972 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.674 Times cited 5 Open Access
Notes ; The authors acknowledge useful discussions with L. Wirtz, A. Molina-Sanchez, and C. Sevik. This work was supported by the ESF-Eurographene project CONGRAN, and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 1.674
Call Number (down) UA @ lucian @ c:irua:140309 Serial 4462
Permanent link to this record
 

 
Author Michel, K.H.; Costamagna; Peeters, F.M.
Title Theory of anharmonic phonons in two-dimensional crystals Type A1 Journal article
Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 91 Issue 91 Pages 134302
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Anharmonic effects in an atomic monolayer thin crystal with honeycomb lattice structure are investigated by analytical and numerical lattice dynamical methods. Starting from a semiempirical model for anharmonic couplings of third and fourth orders, we study the in-plane and out-of-plane (flexural) mode components of the generalized wave vector dependent Gruneisen parameters, the thermal tension and the thermal expansion coefficients as a function of temperature and crystal size. From the resonances of the displacement-displacement correlation functions, we obtain the renormalization and decay rate of in-plane and flexural phonons as a function of temperature, wave vector, and crystal size in the classical and in the quantum regime. Quantitative results are presented for graphene. There, we find that the transition temperature T-alpha from negative to positive thermal expansion is lowered with smaller system size. Renormalization of the flexural mode has the opposite effect and leads to values of T-alpha approximate to 300 K for systems of macroscopic size. Extensive numerical analysis throughout the Brillouin zone explores various decay and scattering channels. The relative importance of normal and umklapp processes is investigated. The work is complementary to crystalline membrane theory and computational studies of anharmonic effects in two-dimensional crystals.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000353031000001 Publication Date 2015-04-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121; 1550-235x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 38 Open Access
Notes ; We thank B. Verberck, D. Lamoen, and A. Dobry for useful comments. We acknowledge funding from the FWO (Belgium)-MINCyT (Argentina) collaborative research project. This work is supported by the EuroGRAPHENE project CONGRAN. ; Approved Most recent IF: 3.836; 2015 IF: 3.736
Call Number (down) UA @ lucian @ c:irua:132512 Serial 4263
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Author Michel, K.H.; Costamagna; Peeters, F.M.
Title Theory of thermal expansion in 2D crystals Type A1 Journal article
Year 2015 Publication Physica status solidi: B: basic research Abbreviated Journal Phys Status Solidi B
Volume 252 Issue 252 Pages 2433-2437
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The thermal expansion alpha(T) in layered crystals is of fundamental and technological interest. As suggested by I. M. Lifshitz in 1952, in thin solid films (crystalline membranes) a negative contribution to alpha(T) is due to anharmonic couplings between in-plane stretching modes and out-of-plane bending (flexural modes). Genuine in-plane anharmonicities give a positive contribution to alpha(T). The competition between these two effects can lead to a change of sign (crossover) from a negative value of alpha(T) in a temperature (T) range T <= T-alpha to a positive value of alpha(T) for T > T-alpha in layered crystals. Here, we present an analytical lattice dynamical theory of these phenomena for a two-dimensional (2D) hexagonal crystal. We start from a Hamiltonian that comprises anharmonic terms of third and fourth order in the lattice displacements. The in-plane and out-of-plane contributions to the thermal expansion are studied as functions of T for crystals of different sizes. Besides, renormalization of the flexural mode frequencies plays a crucial role in determining the crossover temperature T-alpha. Numerical examples are given for graphene where the anharmonic couplings are determined from experiments. The theory is applicable to other layer crystals wherever the anharmonic couplings are known. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000364690400014 Publication Date 2015-08-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1972 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.674 Times cited 21 Open Access
Notes ; We thank B. Verberck, D. Lamoen, and A. Dobry for useful comments. We acknowledge funding from the FWO (Belgium)-MINCyT (Argentina) collaborative research project. This work is supported by the Euro GRAPHENE project CONGRAN. ; Approved Most recent IF: 1.674; 2015 IF: 1.489
Call Number (down) UA @ lucian @ c:irua:130281 Serial 4264
Permanent link to this record
 

 
Author Michel, K.H.; Lamoen, D.; David, W.I.F.
Title Orientational order and disorder in solid C60 : theory and diffraction experiments Type A1 Journal article
Year 1995 Publication Acta crystallographica: section A: foundations of crystallography Abbreviated Journal Acta Crystallogr A
Volume 51 Issue 3 Pages 365-374
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Starting from a microscope model of the intermolecular potential, a unified description is presented of the Bragg scattering law in the orientationally disordered and in the ordered phase of solid C-60. The orientational structure factor is expanded in terms of symmetry-adapted surface harmonics. The expansion coefficients are calculated from theory and compared with experiment Their temperature evolution is studied in the disordered phase at the 260 K transitions and in the ordered phase. In the ordered phase, new results from high-resolution neutron powder diffraction are given. In the disordered phase, space group Fm $($) over bar$$ 3m, the reflections have A(1g) symmetry; in the ordered phase, space group Pa $$($) over bar 3, reflections of T-2g symmetry appear and in addition the A(1g) reflections are renormalized. The orientational density distribution is calculated. The effective crystal-field potential is constructed, its temperature evolution in the ordered phase is studied and related to the occurrence of an orientational glass.
Address
Corporate Author Thesis
Publisher Place of Publication Copenhagen Editor
Language Wos A1995RB59400018 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0108-7673; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.307 Times cited 14 Open Access
Notes Approved CHEMISTRY, MULTIDISCIPLINARY 65/163 Q2 # CRYSTALLOGRAPHY 10/26 Q2 #
Call Number (down) UA @ lucian @ c:irua:12189 Serial 2518
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Author Neek-Amal, M.; Beheshtian, J.; Sadeghi, A.; Michel, K.H.; Peeters, F.M.
Title Boron nitride mono layer : a strain-tunable nanosensor Type A1 Journal article
Year 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 117 Issue 25 Pages 13261-13267
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract The influence of triaxial in-plane strain on the electronic properties of a hexagonal boron-nitride sheet is investigated using density functional theory. Different from graphene, the triaxial strain localizes the molecular orbitals of the boron-nitride flake in its center depending on the direction of the applied strain. The proposed technique for localizing the molecular orbitals that are close to the Fermi level in the center of boron nitride flakes can be used to actualize engineered nanosensors, for instance, to selectively detect gas molecules. We show that the central part of the strained flake adsorbs polar molecules more strongly as compared with an unstrained sheet.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000321236400041 Publication Date 2013-06-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 38 Open Access
Notes ; This work was supported by the EU-Marie Curie IIF postdoc Fellowship/299855 (for M.N.-A.), the ESF EuroGRAPHENE project CONGRAN, the Flemish Science Foundation (FWO-VI), and the Methusalem Funding of the Flemish government. AS. would like to thank the Universiteit Antwerpen for its hospitality. ; Approved Most recent IF: 4.536; 2013 IF: 4.835
Call Number (down) UA @ lucian @ c:irua:109829 Serial 249
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Author Michel, K.H.; Verberck, B.
Title Rigid-plane phonons in layered crystals Type A1 Journal article
Year 2012 Publication Physica status solidi: B: basic research Abbreviated Journal Phys Status Solidi B
Volume 249 Issue 12 Pages 2604-2607
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The determination of the layer number ${\cal N}$ in nanoscale thin layered crystals is a challenging problem of technological relevance. In addition to innovative experimental techniques, a thorough knowledge of the underlying lattice dynamics is required. Starting from phenomenological atomic interaction potentials we have carried out an analytical study of the low-frequency optical phonon dispersions in layered crystals. At the gamma point of the two-dimensional Brillouin zone the optical phonon frequencies correspond to rigid-plane shearing and compression modes. We have investigated graphene multilayers (GML) and hexagonal boron-nitride multilayers (BNML). The frequencies show a characteristic dependence on ${\cal N}$. The results which are represented in the form of fan diagrams are very similar for both materials. Due to charge neutrality within layers Coulomb forces play no role, only van der Waals forces between nearest neighbor layers are relevant. The theoretical results agree with recent low-frequency Raman results on rigid-layer modes [Tan et al., Nature Mater. 11, 294 (2012)] in GML and double-resonant Raman scattering data on rigid-layer compression modes [Herziger et al., Phys. Rev. B 85, 235447 (2012)] in GML. (C) 2012 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim
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Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000312215300072 Publication Date 2012-11-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1972; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.674 Times cited 1 Open Access
Notes ; This work has been supported by the Flemish Science Foundation (FWO-Vl) and the Bijzonder Onderzoeksfonds, Universiteit Antwerpen (BOF-UA). ; Approved Most recent IF: 1.674; 2012 IF: 1.489
Call Number (down) UA @ lucian @ c:irua:105992 Serial 2907
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Author Beheshtian, J.; Sadeghi, A.; Neek-Amal, M.; Michel, K.H.; Peeters, F.M.
Title Induced polarization and electronic properties of carbon-doped boron nitride nanoribbons Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 19 Pages 195433-195438
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The electronic properties of boron nitride nanoribbons (BNNRs) doped with a line of carbon atoms are investigated using density functional calculations. By replacing a line of alternating B and N atoms with carbons, three different configurations are possible depending on the type of the atoms which bond to the carbons. We found very different electronic properties for these configurations: (i) the NCB arrangement is strongly polarized with a large dipole moment having an unexpected direction, (ii) the BCB and NCN arrangements are nonpolar with zero dipole moment, (iii) the doping by a carbon line reduces the band gap regardless of the local arrangement of the borons and the nitrogens around the carbon line, and (iv) the polarization and energy gap of the carbon-doped BNNRs can be tuned by an electric field applied parallel to the carbon line. Similar effects were found when either an armchair or zigzag line of carbon was introduced.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000311694200006 Publication Date 2012-11-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 41 Open Access
Notes ; We would like to thank J. M. Pereira and S. Goedecker for helpful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl), the ESF-EuroGRAPHENE project CONGRAN. M. N.-A is supported by EU-Marie Curie IIF postdoc Fellowship/299522. ; Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number (down) UA @ lucian @ c:irua:105136 Serial 1603
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Author Callebaut, A.K.; Michel, K.H.
Title Microscopic theory of orientational disorder and lattice instability in solid C70 Type A1 Journal article
Year 1995 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 52 Issue 21 Pages 15279-15290
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We have developed a microscopic theory which describes the orientational dynamics of C-70 molecules and its coupling to lattice displacements in the face-centered-cubic phase of C-70 fullerite. The single-molecule orientational density distribution in the disordered phase is calculated. The ferroelastic transition to the rhombohedral phase is investigated. The discontinuity of the orientational order parameter at the phase transition is calculated. It is found that the transition leads to a stretching of the primitive unit cell along a [111] cubic direction. A softening of the elastic constant c(44) at the transition is predicted.
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Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1995TK97900042 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.736 Times cited 20 Open Access
Notes Approved PHYSICS, APPLIED 28/145 Q1 #
Call Number (down) UA @ lucian @ c:irua:104421 Serial 2031
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Author Copley, J.R.D.; Michel, K.H.
Title Multiple orientational order parameters in solid C60 Type A1 Journal article
Year 1997 Publication Physica: B : condensed matter T2 – International Conference on Neutron Scattering, AUG 17-21, 1997, TORONTO, CANADA Abbreviated Journal Physica B
Volume 241 Issue Pages 454-455
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The transition Fm (3) over bar m -->Pa (3) over bar in solid C-60 is driven by the condensation of orientational modes belonging to X-5(+) irreducible representations (irreps) of Fm (3) over bar m. Taking into account irreps up to the manifold l = 12, we have studied the primary and secondary orientational order parameters loops). We have numerically solved the coupled molecular field equations for these oops and calculated the temperature dependence of Bragg reflection intensities. (C) 1998 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000074062600130 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526; ISBN Additional Links UA library record; WoS full record
Impact Factor 1.386 Times cited Open Access
Notes Approved Most recent IF: 1.386; 1997 IF: 0.991
Call Number (down) UA @ lucian @ c:irua:104360 Serial 2228
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