Records |
Author |
Michel, K.H.; Verberck, B. |
Title |
Theory of phonon dispersions and piezoelectricity in multilayers of hexagonal boron-nitride |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
Volume |
248 |
Issue |
11 |
Pages |
2720-2723 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Taking into account covalent, Coulomb and van der Waals interactions, we construct the dynamical matrix and calculate the phonon dispersion relations for multilayer crystals of hexagonal boron-nitride. Coulomb interactions account for a strong overbending of optical phonons. Applying and extending Born's long-wave theory to the case of multilayer crystals, we calculate the piezoelectric stress constant equation image as a function of the number of layers equation image. In agreement with group theory, we find that equation image for equation image even; for an uneven number equation image of layers we obtain equation image, i.e. the piezoelectric constant decreases as equation image. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Berlin |
Editor |
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Language |
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Wos |
000297517100069 |
Publication Date |
2011-10-18 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-1972; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.674 |
Times cited |
13 |
Open Access |
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Notes |
; Discussions with G. Heger, B. Partoens and F. M. Peeters are gratefully acknowledged. 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; 2011 IF: 1.316 |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:94034 |
Serial |
3618 |
Permanent link to this record |
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Author |
Launois, P.; Chorro, M.; Verberck, B.; Albouy, P.-A.; Rouzière, S.; Colson, D.; Forget, A.; Noé, L.; Kataura, H.; Monthioux, M.; Cambedouzou, J. |
Title |
Transformation of C70 peapods into double walled carbon nanotubes |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
Volume |
48 |
Issue |
1 |
Pages |
89-98 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
X-ray diffraction studies comparing the transformation of C(60) and C(70) peapods into double walled carbon nanotubes are presented. The structures of the as-formed DWCNTs are strikingly similar, showing that they are not dependent on the nature of the fullerene precursor. High temperature X-ray diffraction measurements of C(70) peapods below the coalescence temperature show that confined C(70) molecules in large tubes undergo an orientational. transition to free rotations. Fast re-orientations of C(70) molecules allow cyclo-addition between adjacent fullerenes to form, in good agreement with the mechanism of coalescence proposed in the literature for C(60) molecules. (C) 2009 Elsevier Ltd. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000272018800012 |
Publication Date |
2009-08-30 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
ISSN |
0008-6223; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.337 |
Times cited |
27 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 6.337; 2010 IF: 4.896 |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:94389 |
Serial |
3696 |
Permanent link to this record |
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Author |
Michel, K.H.; Verberck, B.; Nikolaev, A.V. |
Title |
Anisotropic packing and one-dimensional fluctuations of C60 molecules in carbon nanotubes |
Type |
A1 Journal article |
Year |
2005 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
95 |
Issue |
18 |
Pages |
185506-185506,4 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The confinement of a C-60 molecule encapsulated in a cylindrical nanotube depends on the tube radius. In small tubes with radius R-T less than or similar to 7 A, a fivefold axis of the molecule coincides with the tube axis. The interaction between C-60 molecules in the nanotube is then described by a O-2-rotor model on a 1D liquid chain with coupling between orientational and displacive correlations. This coupling leads to chain contraction. The structure factor of the 1D liquid is derived. In tubes with a larger radius the molecular centers of mass are displaced off the tube axis. The distinction of two groups of peapods with on- and off-axis molecules suggests an explanation of the apparent splitting of A(g) modes of C-60 in nanotubes measured by resonant Raman scattering. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000232887400041 |
Publication Date |
2005-10-28 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007;1079-7114; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
40 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 8.462; 2005 IF: 7.489 |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:94717 |
Serial |
127 |
Permanent link to this record |
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Author |
Michel, K.H.; Verberck, B.; Nikolaev, A. |
Title |
Mercator maps of orientations of a C60 molecule in single-walled nanotubes with distinct radii |
Type |
A1 Journal article |
Year |
2005 |
Publication |
AIP conference proceedings |
Abbreviated Journal |
|
Volume |
786 |
Issue |
|
Pages |
69-72 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We study the confinement of a C-60 molecule encapsulated in a cylindrical nanotube as a function of the tube radius. Drawing the Mercator maps of the potential, we find two distinct molecular orientations; for tubes with small radii, R-T less than or similar to 7 angstrom, a fivefold axis of the molecule coincides with the tube long axis, for larger radii, R-T less than or similar to 8 angstrom, a threefold axis of the molecule coincides with the tube long axis. These different orientations are caused by the relative importance of the repulsive and the attractive parts of the van der Waals potentials of the molecule with the tube wall for small and large tubes respectively. Experimental evidence is provided by the apparent splitting of A(g) modes of the C-60 molecule in resonant Raman scattering. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
Amer inst physics |
Place of Publication |
Melville |
Editor |
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Language |
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Wos |
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Publication Date |
0000-00-00 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0094-243x |
ISBN |
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Additional Links |
UA library record; WoS full record; |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:94738 |
Serial |
1993 |
Permanent link to this record |
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Author |
Verberck, B.; Nikolaev, A.V.; Michel, K.H. |
Title |
Orientational charge density waves and the metal-insulator transition in polymerized KC60 |
Type |
A1 Journal article |
Year |
2004 |
Publication |
AIP conference proceedings |
Abbreviated Journal |
|
Volume |
723 |
Issue |
|
Pages |
339-342 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Polymerized KC60 undergoes a structural phase transition accompanied by a metal-insulator transition around 50 K. To explain the structural aspect, a mechanism involving small orientational deviations of the valence electron density on every C-60 monomer orientational charge density waves (OCDWs) – has already been proposed earlier. In the present work, we address the metal-insulator transition using the OCDW concept. We are inspired by the analogy between a polymer chain exhibiting an OCDW and a linear atomic chain undergoing a static lattice deformation doubling the unit cell: such a deformation implies a band gap at the zone boundary, yielding an insulating state (Peierls instability). Within our view, a similar mechanism occurs in polymerized KC60; the OCDW plays the role of the lattice deformation. We present tight-binding band structure calculations and conclude that the metal-insulator transition can indeed be explained using OCDWs, but that the threedimensionality of the crystal plays an unexpected key role. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York |
Editor |
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Language |
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Wos |
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Publication Date |
0000-00-00 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0094-243x |
ISBN |
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Additional Links |
UA library record; WoS full record; |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:94831 |
Serial |
2513 |
Permanent link to this record |
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Author |
Verberck, B.; Nikolaev, A.V.; Michel, K.H. |
Title |
Theoretical model for the structural phase transition at the metal-insulator transition in polymerized KC60 |
Type |
A1 Journal article |
Year |
2002 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
Volume |
66 |
Issue |
16 |
Pages |
165425-165425,14 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The recently discovered structural transition in polymerized KC60 at about 50 K results in a doubling of the unit cell volume and accompanies the metal-insulator transition. Here we show that the ((a) over right arrow+(c) over right arrow,(b) over right arrow,(a) over right arrow-(c) over right arrow) superstructure results from small orientational charge density waves along the polymer chains and concomitant displacements of the surrounding K+ ions. The effect is specific for the space group Pmnn of KC60 and is absent in RbC60 and CsC60 (space group I2/m). The mechanism is relevant for the metal-insulator transition. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000179286400135 |
Publication Date |
2002-10-30 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0163-1829;1095-3795; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
10 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 3.836; 2002 IF: NA |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:94907 |
Serial |
3608 |
Permanent link to this record |
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Author |
Verberck, B.; Partoens, B.; Peeters, F.M.; Trauzettel, B. |
Title |
Strain-induced band gaps in bilayer graphene |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
85 |
Issue |
12 |
Pages |
125403-125403,10 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We present a tight-binding investigation of strained bilayer graphene within linear elasticity theory, focusing on the different environments experienced by the A and B carbon atoms of the different sublattices. We find that the inequivalence of the A and B atoms is enhanced by the application of perpendicular strain epsilon(zz), which provides a physical mechanism for opening a band gap, most effectively obtained when pulling the two graphene layers apart. In addition, perpendicular strain introduces electron-hole asymmetry and can result in linear electronic dispersion near the K point. Our findings suggest experimental means for strain-engineered band gaps in bilayer graphene. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000301113200005 |
Publication Date |
2012-03-06 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
53 |
Open Access |
|
Notes |
; The authors would like to acknowledge O. Leenaerts, E. Mariani, K. H. Michel, and J. Schelter for useful discussions. B. V. was financially supported by the Flemish Science Foundation (FWO-Vl). This work was financially supported by the ESF program EuroGraphene under projects CONGRAN and ENTS as well as by the DFG. ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:97181 |
Serial |
3168 |
Permanent link to this record |
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Author |
Michel, K.H.; Verberck, B. |
Title |
Theory of rigid-plane phonon modes in layered crystals |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
85 |
Issue |
9 |
Pages |
094303-094303,11 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The lattice dynamics of low-frequency rigid-plane modes in metallic (graphene multilayers, GML) and in insulating (hexagonal boron-nitride multilayers, BNML) layered crystals is investigated. The frequencies of shearing and compression (stretching) modes depend on the layer number N and are presented in the form of fan diagrams. The results for GML and BNML are very similar. In both cases, only the interactions (van der Waals and Coulomb) between nearest-neighbor planes are effective, while the interactions between more distant planes are screened. A comparison with recent Raman scattering results on low-frequency shear modes in GML [Tan et al., Nat. Mater., in press, doi: 10.1038/nmat3245, (2012)] is made. Relations with the low-lying rigid-plane phonon dispersions in the bulk materials are established. Master curves, which connect the fan diagram frequencies for any given N, are derived. Static and dynamic thermal correlation functions for rigid-layer shear and compression modes are calculated. The results might be of use for the interpretation of friction force experiments on multilayer crystals. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000301646000006 |
Publication Date |
2012-03-19 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
38 |
Open Access |
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Notes |
; The authors are indebted to J. Maultzsch for bringing Ref. 20 to their attention. They thank D. Lamoen, F.M. Peeters, B. Trauzettel, and C. Van Haesendonck for useful discussions. This work has been financially supported by the Research Foundation Flanders (FWO). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:97787 |
Serial |
3619 |
Permanent link to this record |
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Author |
Verberck, B.; Cambedouzou, J.; Vliegenthart, G.A.; Gompper, G.; Launois, P. |
Title |
Monte Carlo studies of C60- and C70-peapods |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Fullerenes, nanotubes, and carbon nanostructures |
Abbreviated Journal |
Fuller Nanotub Car N |
Volume |
20 |
Issue |
4/7 |
Pages |
371-377 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
Abstract |
We present results of Monte Carlo simulations of chains of C-60 and chains of C-70 molecules encapsulated in a single-walled carbon nanotube (SWCNT). We observe the changes in the configuration of the fullerene molecules when varying tube radius and temperature. In particular, the evolution of the pair correlation functions reveal a transition from linear harmonic chain behavior to a hard-sphere liquid upon heating, demonstrating the possibility of tuning properties of C-60- and C-70@SWCNT peapods with radius and temperature. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000304297500015 |
Publication Date |
2012-05-14 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1536-383X;1536-4046; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.35 |
Times cited |
1 |
Open Access |
|
Notes |
; Helpful discussions with K. H. Michel, P.-A. Albouy and C. Bousige are gratefully acknowledged. This work was financially supported by the Research Foundation-Flanders (FWO-Vl). ; |
Approved |
Most recent IF: 1.35; 2012 IF: 0.764 |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:99003 |
Serial |
2200 |
Permanent link to this record |
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Author |
Tarakina, N.V.; Verberck, B. |
Title |
Tubular fullerenes in carbon nanotubes |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Fullerenes, nanotubes, and carbon nanostructures |
Abbreviated Journal |
Fuller Nanotub Car N |
Volume |
20 |
Issue |
4-7 |
Pages |
538-542 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
Abstract |
We investigate the optimal orientations and positions of tubular fullerene molecules C-70, C-80 and C-90 encapsulated in single-walled carbon nanotubes (SWCNTs). We find that increasing the tube radius leads to the following succession of energetically stable regimes: 1) lying molecules positioned on the tube's long axis, 2) tilted molecules on the tube's long axis and 3) lying molecules shifted away from the tube's long axis. In the case of C-70 and C-80 molecules, standing on-axis configurations also occur. Our findings are relevant for the possible application of molecular-orientation-dependent electronic properties of fullerene nanopeapods. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000304297500045 |
Publication Date |
2012-05-14 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1536-383X;1536-4046; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.35 |
Times cited |
|
Open Access |
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Notes |
; This work was financially supported by the Research Foundation – Flanders (FWO-Vl). B. V. is a Postdoctoral Fellow of the Research Foundation-Flanders (FWO-Vl). ; |
Approved |
Most recent IF: 1.35; 2012 IF: 0.764 |
Call Number ![sorted by Call Number field, ascending order (up)](img/sort_asc.gif) |
UA @ lucian @ c:irua:99004 |
Serial |
3737 |
Permanent link to this record |