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“Electron mobility in two coupled &delta, layers”. Hai GQ, Studart N, Peeters FM, Physical review : B : condensed matter and materials physics 52, 11273 (1995)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.736
Times cited: 24
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“Multisubband electron transport in δ-doped semiconductor systems”. Hai GQ, Studart N, Peeters FM, Physical review : B : condensed matter and materials physics 52, 8363 (1995)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.736
Times cited: 65
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“Effects of intersubband interaction on multisubband electron transport in single and double quantum wells”. Hai GQ, Studart N, Marques GE, Peeters FM, Koenraad PM, Physica. E: Low-dimensional systems and nanostructures 2, 222 (1998). http://doi.org/10.1016/S1386-9477(98)00048-4
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.221
Times cited: 3
DOI: 10.1016/S1386-9477(98)00048-4
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“Interface effects on magnetopolarons in GaAs/AlxGa1-xAs quantum wells at high magnetic fields”. Hai GQ, Peeters FM, Studart N, Wang YJ, McCombe BD, Physical review : B : condensed matter and materials physics 58, 7822 (1998). http://doi.org/10.1103/PhysRevB.58.7822
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 8
DOI: 10.1103/PhysRevB.58.7822
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“Effects of intersubband coupling on Friedel oscillations in quasi-two-dimensional electron systems”. Hai GQ, Peeters FM, Studart N, Marques GE, Superlattices and microstructures 25, 185 (1999). http://doi.org/10.1006/spmi.1998.0635
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.123
Times cited: 2
DOI: 10.1006/spmi.1998.0635
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“Screening of the electron-phonon interaction in quasi-one-dimensional semiconductor structures”. Hai GQ, Peeters FM, Devreese JT, Wendler L, Physical review : B : condensed matter and materials physics 48, 12016 (1993). http://doi.org/10.1103/PhysRevB.48.12016
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 3.736
Times cited: 41
DOI: 10.1103/PhysRevB.48.12016
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“Electron optical-phonon coupling in GaAs/AlxGa1-xAs quantum wells due to interface, slab and half-space modes”. Hai GQ, Peeters FM, Devreese JT, Physical review : B : condensed matter and materials physics 48, 4666 (1993). http://doi.org/10.1103/PhysRevB.48.4666
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 3.736
Times cited: 102
DOI: 10.1103/PhysRevB.48.4666
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“Interface optical phonon mode coupling in GaAs/AlAs quantum wells at high magnetic fields”. Hai GQ, Peeters FM, Devreese JT, Physica: B : condensed matter 184, 289 (1993). http://doi.org/10.1016/0921-4526(93)90367-F
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 1.319
Times cited: 3
DOI: 10.1016/0921-4526(93)90367-F
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“Polaron-cyclotron-resonance spectrum resulting from interface- and slab-phonon modes in a GaAs/AlAs quantum well”. Hai GQ, Peeters FM, Devreese JT, Physical review : B : condensed matter and materials physics 47, 10358 (1993). http://doi.org/10.1103/PhysRevB.47.10358
Abstract: The effects of interface optical-phonon and confined slab LO-phonon modes on the polaron cyclotron-resonance frequency are investigated for a GaAs/AlAs quantum well. Using degenerate second-order perturbation theory, the polaron Landau levels are calculated and the polaron resonant region is investigated. In order to know the relative importance of the different resonant frequencies we present a full calculation of the magneto-optical absorption spectrum. At a fixed magnetic field we found four different peaks in the absorption spectrum. The relative oscillator strength of the different peaks changes with increasing magnetic field. For comparative purposes, the polaron Landau levels and cyclotron mass are also calculated using only the bulk LO-phonon modes. The influence of the finiteness of the confinement potential is investigated. We found that the interface-phonon modes influence the magnetopolaron resonance considerably near the optical-phonon frequencies for narrow wells. In the limit of zero magnetic field we recover our previous results and in the case of an infinite-barrier quantum well we are able to recover the results for a two- and three-dimensional system.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 3.736
Times cited: 69
DOI: 10.1103/PhysRevB.47.10358
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“Polaron cyclotron resonance spectrum with interface optical phonon modes in GaAs/AlAs quantum wells”. Hai GQ, Peeters FM, Devreese JT Kluwer, Dordrecht, page 243 (1993).
Keywords: H3 Book chapter; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
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“Magnetopolaron effect in parabolic quantum wells in tilted magnetic fields”. Hai GQ, Peeters FM, Physical review : B : condensed matter and materials physics 60, 8984 (1999). http://doi.org/10.1103/PhysRevB.60.8984
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 36
DOI: 10.1103/PhysRevB.60.8984
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“Optically detected magnetophonon resonance in polar semiconductors GaAs”. Hai GQ, Peeters FM, Physical review : B : condensed matter and materials physics 60, 16513 (1999). http://doi.org/10.1103/PhysRevB.60.16513
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 24
DOI: 10.1103/PhysRevB.60.16513
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“Intersubband-coupling and screening effects on the electron transport in a quasi-two-dimensional δ-doped semiconductor system”. Hai G-Q, Studart N, Peeters FM, Koenraad PM, Wolter JH, Journal of applied physics 80, 5809 (1996). http://doi.org/10.1063/1.363573
Abstract: The effects due to intersubband coupling and screening on the ionized impurity scattering are studied for a quasi-two-dimensional electron system in delta-doped semiconductors. We found that intersubband coupling plays an essential role in describing the screening properties and the effect of ionized impurity scattering on the mobility in a multisubband system. At the onset of the occupation of a higher subband, the screening due to the intersubband coupling leads to a reduction of the small angle scattering rate in the lower subband. We showed that such an effect is significant in a delta-doped quantum well and results in a pronounced increase of the quantum mobility at the onset of the occupation of a higher subband. (C) 1996 American Institute of Physics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.183
Times cited: 40
DOI: 10.1063/1.363573
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“Polaron effects on cyclotron mass due to interface and slab phonons in GaAs/AlGaAs quantum wells”. Hai G-Q, Studart N, Peeters FM, Brazilian journal of physics 26, 219 (1996)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.81
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“Hamiltonian of a many-electron system with single-electron and electron-pair states in a two-dimensional periodic potential”. Hai G-Q, Peeters FM, European physical journal : B : condensed matter and complex systems 88, 20 (2015). http://doi.org/10.1140/epjb/e2014-50686-x
Abstract: Based on the metastable electron-pair energy band in a two-dimensional (2D) periodic potential obtained previously by Hai and Castelano [J. Phys.: Condens. Matter 26, 115502 (2014)], we present in this work a Hamiltonian of many electrons consisting of single electrons and electron pairs in the 2D system. The electron-pair states are metastable of energies higher than those of the single-electron states at low electron density. We assume two different scenarios for the single-electron band. When it is considered as the lowest conduction band of a crystal, we compare the obtained Hamiltonian with the phenomenological model Hamiltonian of a boson-fermion mixture proposed by Friedberg and Lee [Phys. Rev. B 40, 6745 (1989)]. Single-electron-electron-pair and electron-pair-electron-pair interaction terms appear in our Hamiltonian and the interaction potentials can be determined from the electron-electron Coulomb interactions. When we consider the single-electron band as the highest valence band of a crystal, we show that holes in this valence band are important for stabilization of the electron-pair states in the system.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.461
Times cited: 2
DOI: 10.1140/epjb/e2014-50686-x
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“Electron pairing: from metastable electron pair to bipolaron”. Hai G-Q, Candido L, Brito BGA, Peeters FM, Journal of physics communications 2, Unsp 035017 (2018). http://doi.org/10.1088/2399-6528/AAAEE0
Abstract: Starting from the shell structure in atoms and the significant correlation within electron pairs, we distinguish the exchange-correlation effects between two electrons of opposite spins occupying the same orbital from the average correlation among many electrons in a crystal. In the periodic potential of the crystal with lattice constant larger than the effective Bohr radius of the valence electrons, these correlated electron pairs can form a metastable energy band above the corresponding single-electron band separated by an energy gap. In order to determine if these metastable electron pairs can be stabilized, we calculate the many-electron exchange-correlation renormalization and the polaron correction to the two-band system with single electrons and electron pairs. We find that the electron-phonon interaction is essential to counterbalance the Coulomb repulsion and to stabilize the electron pairs. The interplay of the electron-electron and electron-phonon interactions, manifested in the exchange-correlation energies, polaron effects, and screening, is responsible for the formation of electron pairs (bipolarons) that are located on the Fermi surface of the single-electron band.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 9
DOI: 10.1088/2399-6528/AAAEE0
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“Visualizing redox orbitals and their potentials in advanced lithium-ion battery materials using high-resolution x-ray Compton scattering”. Hafiz H, Suzuki K, Barbiellini B, Orikasa Y, Callewaert V, Kaprzyk S, Itou M, Yamamoto K, Yamada R, Uchimoto Y, Sakurai Y, Sakurai H, Bansil A, Science Advances 3, e1700971 (2017). http://doi.org/10.1126/sciadv.1700971
Abstract: Reduction-oxidation (redox) reactions are the key processes that underlie the batteries powering smartphones, laptops, and electric cars. A redox process involves transfer of electrons between two species. For example, in a lithium-ion battery, current is generated when conduction electrons from the lithium anode are transferred to the redox orbitals of the cathode material. The ability to visualize or image the redox orbitals and how these orbitals evolve under lithiation and delithiation processes is thus of great fundamental and practical interest for understanding the workings of battery materials. We show that inelastic scattering spectroscopy using high-energy x-ray photons (Compton scattering) can yield faithful momentum space images of the redox orbitals by considering lithium iron phosphate (LiFePO4 or LFP) as an exemplar cathode battery material. Our analysis reveals a new link between voltage and the localization of transition metal 3d orbitals and provides insight into the puzzling mechanism of potential shift and how it is connected to the modification of the bond between the transition metal and oxygen atoms. Our study thus opens a novel spectroscopic pathway for improving the performance of battery materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Times cited: 9
DOI: 10.1126/sciadv.1700971
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“Self-inhibition can limit biologically enhanced TCE dissolution from a TCE DNAPL”. Haest PJ, Springael D, Seuntjens P, Smolders E, Chemosphere 89, 1369 (2012). http://doi.org/10.1016/J.CHEMOSPHERE.2012.05.097
Abstract: Biodegradation of trichloroethene (TCE) near a Dense Non Aqueous Phase Liquid (DNAPL) can enhance the dissolution rate of the DNAPL by increasing the concentration gradient at the DNAPL-water interface. Two-dimensional flow-through sand boxes containing a ICE DNAPL and inoculated with a TCE dechlorinating consortium were set up to measure this bio-enhanced dissolution under anaerobic conditions. The total mass of TCE and daughter products in the effluent of the biotic boxes was 3-6 fold larger than in the effluent of the abiotic box. However, the mass of daughter products only accounted for 19-55% of the total mass of chlorinated compounds in the effluent, suggesting that bio-enhanced dissolution factors were maximally 1.3-2.2. The enhanced dissolution most likely primarily resulted from variable DNAPL distribution rather than biodegradation. Specific dechlorination rates previously determined in a stirred liquid medium were used in a reactive transport model to identify the rate limiting factors. The model adequately simulated the overall TCE degradation when predicted resident microbial numbers approached observed values and indicated an enhancement factor for TCE dissolution of 1.01. The model shows that dechlorination of TCE in the 20 box was limited due to the short residence time and the self-inhibition of the TCE degradation. A parameter sensitivity analysis predicts that the bio-enhanced dissolution factor for this TCE source zone can only exceed a value of 2 if the TCE self-inhibition is drastically reduced (when a TCE tolerant dehalogenating community is present) or if the DNAPL is located in a low-permeable layer with a small Darcy velocity. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CHEMOSPHERE.2012.05.097
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“HREM study of fluorinated Nd2CuO4”. Hadermann J, Van Tendeloo G, Abakumov AM, Rozova MG, Antipov EV, Journal of solid state chemistry 157, 56 (2001). http://doi.org/10.1006/jssc.2000.9038
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 7
DOI: 10.1006/jssc.2000.9038
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“Structural transformation in fluorinated LaACuGaO5 (A=Ca, Sr) brownmillerites”. Hadermann J, Van Tendeloo G, Abakumov AM, Pavlyuk BP, Rozova MG, Antipov EV, International journal of inorganic materials 2, 493 (2000). http://doi.org/10.1016/S1466-6049(00)00072-6
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 13
DOI: 10.1016/S1466-6049(00)00072-6
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“Transmission electron microscopy and structural phase transitions in anion-deficient perovskite-based oxides”. Hadermann J, Van Tendeloo G, Abakumov AM, Acta crystallographica: section A: foundations of crystallography 61, 77 (2005). http://doi.org/10.1107/S0108767304023013
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 5.725
Times cited: 18
DOI: 10.1107/S0108767304023013
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“The (3 + 2)D structure of oxygen deficient LaSrCuO3.52”. Hadermann J, Pérez O, Créon N, Michel C, Hervieu M, Journal of materials chemistry 17, 2344 (2007). http://doi.org/10.1039/b701449j
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 7
DOI: 10.1039/b701449j
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“Introducton to the special issue on electron crystallography”. Hadermann J, Palatinus L, And Materials 75, 462 (2019). http://doi.org/10.1107/S2052520619010783
Keywords: Editorial; Electron microscopy for materials research (EMAT)
Times cited: 2
DOI: 10.1107/S2052520619010783
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“Suppression of modulations in fluorinated Bi-2201 phases”. Hadermann J, Khasanova NR, Van Tendeloo G, Abakumov AM, Rozova MG, Alekseeva AM, Antipov EV, Journal of solid state chemistry 156, 445 (2001). http://doi.org/10.1006/jssc.2000.9020
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 8
DOI: 10.1006/jssc.2000.9020
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“Anion ordering in fluorinated La2CuO4”. Hadermann J, Abakumov AM, Van Tendeloo G, Shpanchenko RV, Oleinikov PN, Antipov EV s.l., page 133 (1999).
Keywords: H1 Book chapter; Electron microscopy for materials research (EMAT)
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“Comment on ALaMn2O6-y (A = K, Rb): novel ferromagnetic manganites exhibiting negative giant magnetoresistance”. Hadermann J, Abakumov AM, Van Rompaey S, Mankevich AS, Korsakov IE, Chemistry of materials 21, 2000 (2009). http://doi.org/10.1021/cm900298a
Keywords: Editorial; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 4
DOI: 10.1021/cm900298a
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“Solving the structure of Li ion battery materials with precession electron diffraction : application to Li2CoPo4F”. Hadermann J, Abakumov AM, Turner S, Hafideddine Z, Khasanova NR, Antipov EV, Van Tendeloo G, Chemistry of materials 23, 3540 (2011). http://doi.org/10.1021/cm201257b
Abstract: The crystal structure of the Li2CoPO4F high-voltage cathode for Li ion rechargeable batteries has been completely solved from precession electron diffraction (PED) data, including the location of the Li atoms. The crystal structure consists of infinite chains of CoO4F2 octahedra sharing common edges and linked into a 3D framework by PO4 tetrahedra. The chains and phosphate anions together delimit tunnels filled with the Li atoms. This investigation demonstrates that PED can be successfully applied for obtaining structural information on a variety of Li-containing electrode materials even from single micrometer-sized crystallites.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 46
DOI: 10.1021/cm201257b
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“Expanding the Ruddlesden-Popper manganite family : the n=3 La3.2Ba0.8Mn3O10 Member”. Hadermann J, Abakumov AM, Tsirlin AA, Rozova MG, Sarakinou E, Antipov EV, Inorganic chemistry 51, 11487 (2012). http://doi.org/10.1021/ic301332e
Abstract: La3.2Ba0.8Mn3O10, a representative of the rare n = 3 members of the Ruddlesden-Popper manganites A(n+1)Mn(n)O(3n+1), was synthesized in an evacuated sealed silica tube. Its crystal structure was refined from a combination of powder X-ray diffraction (PXD) and precession electron diffraction (PED) data, with the rotations of the MnO6 octahedra described within the symmetry-adapted mode approach (space group Cccm, a = 29.068(1) angstrom, b = 5.5504(5) angstrom, c = 5.5412(5) angstrom; PXD RF = 0.053, RP = 0.026; PED RF = 0.248). The perovskite block in La3.2Ba0.8Mn3O10 features an octahedral tilting distortion with out-of-phase rotations of the Mn06 octahedra according to the (Phi,Phi,0)(Phi,Phi,0) mode, observed for the first time in the n = 3 Ruddlesden-Popper structures. The Mn06 octahedra demonstrate a noticeable deformation with the elongation of two apical Mn-O bonds due to the Jahn-Teller effect in the Mn3+ cations. The relationships between the octahedral tilting distortion, the ionic radii of the cations at the A- and B-positions, and the mismatch between the perovslcite and rock-salt blocks of the Ruddlesden-Popper structure are discussed. At low temperatures, La3.2Ba0.8Mn3O10 reveals a sizable remnant magnetization of about 1.3 mu(B)/Mn at 2K, and shows signatures of spin freezing below 150 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 2
DOI: 10.1021/ic301332e
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“Direct space structure solution from precession electron diffraction data: resolving heavy and light scatterers in Pb13Mn9O25”. Hadermann J, Abakumov AM, Tsirlin AA, Filonenko VP, Gonnissen J, Tan H, Verbeeck J, Gemmi M, Antipov EV, Rosner H, Ultramicroscopy 110, 881 (2010). http://doi.org/10.1016/j.ultramic.2010.03.012
Abstract: The crystal structure of a novel compound Pb13Mn9O25 has been determined through a direct space structure solution with a Monte-Carlo-based global optimization using precession electron diffraction data (a=14.177(3) Å, c=3.9320(7) Å, SG P4/m, RF=0.239) and compositional information obtained from energy dispersive X-ray analysis and electron energy loss spectroscopy. This allowed to obtain a reliable structural model even despite the simultaneous presence of both heavy (Pb) and light (O) scattering elements and to validate the accuracy of the electron diffraction-based structure refinement. This provides an important benchmark for further studies of complex structural problems with electron diffraction techniques. Pb13Mn9O25 has an anion- and cation-deficient perovskite-based structure with the A-positions filled by the Pb atoms and 9/13 of the B positions filled by the Mn atoms in an ordered manner. MnO6 octahedra and MnO5 tetragonal pyramids form a network by sharing common corners. Tunnels are formed in the network due to an ordered arrangement of vacancies at the B-sublattice. These tunnels provide sufficient space for localization of the lone 6s2 electron pairs of the Pb2+ cations, suggested as the driving force for the structural difference between Pb13Mn9O25 and the manganites of alkali-earth elements with similar compositions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 24
DOI: 10.1016/j.ultramic.2010.03.012
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“New perovskite-based manganite Pb2Mn2O5”. Hadermann J, Abakumov AM, Perkisas T, d' Hondt H, Tan H, Verbeeck J, Filonenko VP, Antipov EV, Van Tendeloo G, Journal of solid state chemistry 183, 2190 (2010). http://doi.org/10.1016/j.jssc.2010.07.032
Abstract: A new perovskite based compound Pb2Mn2O5 has been synthesized using a high pressure high temperature technique. The structure model of Pb2Mn2O5 is proposed based on electron diffraction, high angle annular dark field scanning transmission electron microscopy and high resolution transmission electron microscopy. The compound crystallizes in an orthorhombic unit cell with parameters a=5.736(1)Å≈√2a p p p (a p the parameter of the perovskite subcell) and space group Pnma. The Pb2Mn2O5 structure consists of quasi two-dimensional perovskite blocks separated by 1/2[110] p (1̄01) p crystallographic shear planes. The blocks are connected to each other by chains of edge-sharing MnO5 distorted tetragonal pyramids. The chains of MnO5 pyramids and the MnO6 octahedra of the perovskite blocks delimit six-sided tunnels accommodating double chains of Pb atoms. The tunnels and pyramidal chains adopt two mirror-related configurations (left L and right R) and layers consisting of chains and tunnels of the same configuration alternate in the structure according to an -LRLR-sequence. The sequence is sometimes locally violated by the appearance of -LL- or -RR-fragments. A scheme is proposed with a JahnTeller distortion of the MnO6 octahedra with two long and two short bonds lying in the ac plane, along two perpendicular orientations within this plane, forming a d-type pattern.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 8
DOI: 10.1016/j.jssc.2010.07.032
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