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Resonance Tunneling Phenomena in Two-Dimensional Multilayer van der Waals Crystalline Systems
摘要： Works, mostly experimental, concerning the most interesting features of application of the resonant tunneling spectroscopy to a new type of heterosystems, van der Waals heterostructures, have been briefly reviewed. These heterostructures appeared after the recent discovery of two-dimensional crystals, which are a new class of materials beginning with graphene. The role of the angular matching of crystal lattices of conducting graphene electrodes of van der Waals systems in carrier tunneling between them has been analyzed together with the closely related problems of satisfaction of conservation laws in tunneling transitions. Manifestations of multiparticle correlation interactions between carriers in van der Waals systems such as Wigner crystallization of electrons in a two-dimensional electron gas in a magnetic field and Bose condensation of excitons in parallel two-dimensional electron gases have been briefly discussed.
关键词： angular matching,momentum conservation,resonant tunneling spectroscopy,graphene,two-dimensional crystals,Wigner crystallization,van der Waals heterostructures,Bose condensation
更新于2025-09-23 15:23:52
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Impact of Defects on Electronic Properties of Heterostructures Constructed From Monolayers of Transition Metal Dichalcogenides
摘要： Electronic properties of heterostructures composed of two single molecular layers (monolayers) of MoS2, WS2, WSe2, and MoSe2 are ab initio simulated with an emphasis to the stacking peculiarities and an influence of point defects in their lattices. MoS2/MoSe2, MoS2/WS2, WS2/WSe2, and MoSe2/WSe2 heterostructures with the monolayers shifted like in the bulk material have been found to behave like semiconductors with the energy gaps of 0.88, 1.25, 1.06, and 1.07 eV, respectively. Such heterostructures possess indirect gaps in contrast to individual monolayers, while direct-gap character is preserved in two layer stacking variants in WS2/WSe2 heterostructures and in MoS2/MoSe2 heterostructure with mirror stacking of the monolayers. Vacancies and Te atoms substituting other chalcogen atoms reduce the band gaps. The calculated orbital compositions of first direct band gap transitions in the defect-free heterostructures and those with the point defects have demonstrated d-electrons of Mo or W atoms to be mainly involved in the transitions.
关键词： defects,two-dimensional crystals,transition metal dichalcogenides,heterostructures,electronic structure
更新于2025-09-23 15:22:29