“Effect of mismatched electron-hole effective masses on superfluidity in double layer solid-state systems”. Conti S, Perali A, Peeters FM, Neilson D, Condensed Matter 6, 14 (2021). http://doi.org/10.3390/CONDMAT6020014
Abstract: Superfluidity has been predicted and now observed in a number of different electron-hole double-layer semiconductor heterostructures. In some of the heterostructures, such as GaAs and Ge-Si electron-hole double quantum wells, there is a strong mismatch between the electron and hole effective masses. We systematically investigate the sensitivity to unequal masses of the superfluid properties and the self-consistent screening of the electron-hole pairing interaction. We find that the superfluid properties are insensitive to mass imbalance in the low density BEC regime of strongly-coupled boson-like electron-hole pairs. At higher densities, in the BEC-BCS crossover regime of fermionic pairs, we find that mass imbalance between electrons and holes weakens the superfluidity and expands the density range for the BEC-BCS crossover regime. This permits screening to kill the superfluid at a lower density than for equal masses.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 1
DOI: 10.3390/CONDMAT6020014
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“Neutron and X-ray scattering cross sections of orientationally disordered solid C60”. Copley JRD, Michel KH, Journal Of Physics-Condensed Matter 5, 4353 (1993)
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 2.346
Times cited: 34
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“Neutron and X-ray-scattering cross sections of orientationally disordered solid C60”. Copley JRD, Michel KH, Journal of physics : condensed matter 5, 4353 (1993). http://doi.org/10.1088/0953-8984/5/26/008
Abstract: Differential cross sections for neutron and x-ray scattering have been derived for the orientationally disordered phase of solid C60. Interaction centres are placed at nuclei and at the centres of interatomic bonds. Bragg and diffuse scattering cross sections, for single crystals and for powders, are formulated using symmetry-adapted rotator functions. Thermal averages are calculated taking account of crystal field effects. Thermally averaged orientational distribution functions have also been calculated.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.346
Times cited: 34
DOI: 10.1088/0953-8984/5/26/008
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“Normal and hot electro-phonon resonance effect in a quasi-two-dimensional semiconductor system”. Xu W, Peeters FM, Devreese JT, Journal of physics : condensed matter 5, 2307 (1993). http://doi.org/10.1088/0953-8984/5/15/004
Abstract: The electro-phonon resonance effect is a consequence of a resonant interaction between two electric subbands mediated by an optical phonon. It occurs in a quasi-two-dimensional electron system each time the energy difference between two electric subbands equals the energy of a Lo phonon. We study the influence of this effect on the electron mobility by using the momentum balance equation. The temperature and electron density dependences of the resonances are studied in the linear and non-linear response regimes.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Impact Factor: 2.346
Times cited: 18
DOI: 10.1088/0953-8984/5/15/004
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“Transition metal dichalcogenides as strategy for high temperature electron-hole superfluidity”. Conti S, Neilson D, Peeters FM, Perali A, Condensed Matter 5, 22 (2020). http://doi.org/10.3390/CONDMAT5010022
Abstract: Condensation of spatially indirect excitons, with the electrons and holes confined in two separate layers, has recently been observed in two different double layer heterostructures. High transition temperatures were reported in a double Transition Metal Dichalcogenide (TMD) monolayer system. We briefly review electron-hole double layer systems that have been proposed as candidates for this interesting phenomenon. We investigate the double TMD system WSe2/hBN/MoSe2, using a mean-field approach that includes multiband effects due to the spin-orbit coupling and self-consistent screening of the electron-hole Coulomb interaction. We demonstrate that the transition temperature observed in the double TMD monolayers, which is remarkably high relative to the other systems, is the result of (i) the large electron and hole effective masses in TMDs, (ii) the large TMD band gaps, and (iii) the presence of multiple superfluid condensates in the TMD system. The net effect is that the superfluidity is strong across a wide range of densities, which leads to high transition temperatures that extend as high as TBKT=150 K.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 13
DOI: 10.3390/CONDMAT5010022
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“Substrate-induced proximity effect in superconducting niobium nanofilms”. Rezvani SJ, Perali A, Fretto M, De Leo N, Flammia L, Milošević, M, Nannarone S, Pinto N, Condensed Matter 4, 4 (2018). http://doi.org/10.3390/CONDMAT4010004
Abstract: Structural and superconducting properties of high-quality niobium nanofilms with different thicknesses are investigated on silicon oxide (SiO2) and sapphire substrates. The role played by the different substrates and the superconducting properties of the Nb films are discussed based on the defectivity of the films and on the presence of an interfacial oxide layer between the Nb film and the substrate. The X-ray absorption spectroscopy is employed to uncover the structure of the interfacial layer. We show that this interfacial layer leads to a strong proximity effect, especially in films deposited on a SiO2 substrate, altering the superconducting properties of the Nb films. Our results establish that the critical temperature is determined by an interplay between quantum-size effects, due to the reduction of the Nb film thicknesses, and proximity effects. The detailed investigation here provides reference characterizations and has direct and important implications for the fabrication of superconducting devices based on Nb nanofilms.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 3
DOI: 10.3390/CONDMAT4010004
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“The hot electron distribution of two-dimensional electrons in a polar semiconductor at zero temperature”. Xu W, Peeters FM, Devreese JT, Journal of physics: C: condensed matter 3, 1783 (1991)
Keywords: A3 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
Times cited: 1
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“Hierarchical zeolite single-crystal reactor for excellent catalytic efficiency”. Sun M-H, Zhou J, Hu Z-Y, Chen L-H, Li L-Y, Wang Y-D, Xie Z-K, Turner S, Van Tendeloo G, Hasan T, Su B-L, Matter 3, 1226 (2020). http://doi.org/10.1016/J.MATT.2020.07.016
Abstract: As a size- and shape-selective catalyst, zeolites are widely used in petroleum and fine-chemicals processing. However, their small micropores severely hinder molecular diffusion and are sensitive to coke formation. Hierarchically porous zeolite single crystals with fully interconnected, ordered, and tunable multimodal porosity at macro-, meso-, and microlength scale, like in leaves, offer the ideal solution. However, their synthesis remains highly challenging. Here, we report a versatile confined zeolite crystallization process to achieve these superior properties. Such zeolite single crystals lead to significantly improved mass transport properties by shortening the diffusion length while maintaining shape-selective properties, endowing them with a high efficiency of zeolite crystals, enhanced catalytic activities and lifetime, highly reduced coke formation, and reduced deactivation rate in bulky-molecule reactions and methanol-to-olefins process. Their industrial utilization can lead to the design of innovative and intensified reactors and processes with highly enhanced efficiency and minimum energy consumption.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1016/J.MATT.2020.07.016
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“Calculation of binary and ternary metallic immiscible clusters with icosahedral structures”. Dzhurakhalov AA, Atanasov I, Hou M, Physical review : B : condensed matter and materials physics , 115415 (2008). http://doi.org/10.1103/PHYSREVB.77.115415
Abstract: Recently, core-shell Ag-Co, Ag-Cu, and “onionlike” Cu-Co equilibrium configurations were predicted in the case of isolated face centered cubic (fcc) bimetallic clusters, and three shell onionlike configurations were predicted in the case of ternary metallic clusters with spherical and truncated octahedral morphologies. In the present paper, immiscible binary CuCo and ternary AgCuCo clusters with icosahedral structures are studied as functions of their size and composition. Clusters studied are formed by 13, 55, 147, 309, and 561 atoms corresponding to the five smallest possible closed shell icosahedral structures. An embedded atom model potential is used to describe their cohesion. Equilibrium configurations are investigated by means of Metropolis Monte Carlo free energy minimization in the (NPT) canonical ensemble. Most simulations are achieved at 10 and 300 K. The effect of temperature on segregation ordering is systematically investigated. Selected cases are used to identify the effect of size and composition on melting. In contrast with fcc clusters, homogeneous onionlike configurations of binary clusters are not predicted. When it is allowed by the composition, a complete outer shell is formed by Cu in binary Cu-Co clusters and by Ag in ternary Ag-Cu-Co clusters. Depending on temperature, Co may precipitate into decahedral groups under the Cu vertices of the icosahedra in binary clusters, while the Co-Cu configuration in ternary clusters drastically depends on the Ag coating. Despite the multicomponent character of the clusters and the immiscibility of the species forming them, for most compositions and sizes, equilibrium structures remain close to perfectly icosahedral at 10 K as well as at 300 K.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.836
Times cited: 11
DOI: 10.1103/PHYSREVB.77.115415
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