MoTe2 is a good match for Gel by preserving quantum spin Hall phase

Quantum spin Hall (QSH) insulator is a new class of materials that is quickly becoming mainstream in condensed-matter physics. The main obstacle for the development of QSH insulators is that their strong interactions with substrates make them difficult to study experimentally. In this study, using d...

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Published in:纳米研究:英文版 2017, Vol.10 (8), p.2823-2832
Main Author: Xinru Li Ying Dai Chengwang Niu Yandong Ma Wei Wei Baibiao Huang
Format: Article
Language:English
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Summary:Quantum spin Hall (QSH) insulator is a new class of materials that is quickly becoming mainstream in condensed-matter physics. The main obstacle for the development of QSH insulators is that their strong interactions with substrates make them difficult to study experimentally. In this study, using density functional theory, we discovered that MoTe2 is a good match for a GeI monolayer. The thermal stability of a van der Waals GeI/MoTe2 heterosheet was examined via molecular-dynamics simulations. Simulated scanning tunneling microscopy revealed that the GeI monolayer perfectly preserves the bulked honeycomb structure of MoTe2. The GeI on MoTe2 was confirmed to maintain its topological band structure with a sizable indirect bulk bandgap of 0.24 eV by directly calculating the spin Chern number to be -1. As expected, the electron mobility of the GeI is enhanced by MoTe2 substrate restriction. According to deformation- potential theory with the effective-mass approximation, the electron mobility of GeI/MoTe2 was estimated as 372.7 cm^2·s^-1·V^-1 at 300 K, which is 20 times higher than that of freestanding GeI. Our research shows that traditional substrates always destroy the topological states and hinder the electron transport in QSH insulators, and pave way for the further realization and utilization of QSH insulators at room temperature.
ISSN:1998-0124
1998-0000