scholarly journals Trivial and inverted Dirac bands and the emergence of quantum spin Hall states in graphene on transition-metal dichalcogenides

2016 ◽  
Vol 93 (15) ◽  
Author(s):  
Martin Gmitra ◽  
Denis Kochan ◽  
Petra Högl ◽  
Jaroslav Fabian
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Quantum Spin ◽  
Metal Dichalcogenides ◽  
Hall States ◽  
Quantum Spin Hall

scholarly journals Tunable topology and berry curvature dipole in transition metal dichalcogenide Janus monolayers

2021 ◽  
Author(s):  
Nesta Joseph ◽  
Saswata Roy ◽  
Awadhesh Narayan
Keyword(s):  
Transition Metal ◽  
Hall Effect ◽  
Transition Metal Dichalcogenides ◽  
Tight Binding ◽  
Quantum Spin ◽  
Transition Metal Dichalcogenide ◽  
Berry Curvature ◽  
Asymmetric Structures ◽  
Non Linear ◽  
Metal Dichalcogenides

Abstract Janus transition metal dichalcogenides, with intrinsic mirror asymmetry, exhibit a wide array of interesting properties. In this work, we study Janus monolayers derived from WTe2 using first-principles and tight-binding calculations. We discover that WSeTe and WSTe are topologically trivial, in contrast to the parent quantum spin Hall insulator WTe2. Motivated by the growing interest in non-linear Hall effect, which also requires asymmetric structures, we investigate the Berry curvature and its dipole in these Janus systems and find that they exhibit strikingly large values of Berry curvature dipole, despite being in the topologically trivial phase. We track down the origin of this behaviour and put forth a low-energy massive Dirac model to understand the central features of our ab inito computations. Our predictions introduce Janus monolayers as promising new platforms for exploring as well as engineering non-linear Hall effect.

scholarly journals Floquet band engineering and topological phase transitions in 1T’ transition metal dichalcogenides

2D Materials ◽  
2022 ◽  
Author(s):  
Xiangru Kong ◽  
Wei Luo ◽  
Linyang Li ◽  
Mina Yoon ◽  
Tom Berlijn ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Tight Binding ◽  
Polarized Light ◽  
Quantum Spin ◽  
Topological Phase ◽  
Circularly Polarized Light ◽  
Band Engineering ◽  
Metal Dichalcogenides

Abstract Using ab initio tight-binding approaches, we investigate Floquet band engineering of the 1T’ phase of transition metal dichalcogenides (MX2, M = W, Mo and X = Te, Se, S) monolayers under the irradiation with circularly polarized light. Our first principles calculations demonstrate that light can induce important transitions in the topological phases of this emerging materials family. For example, upon irradiation, Te-based MX2 undergoes a phase transition from quantum spin Hall (QSH) semimetal to time-reversal symmetry broken QSH insulator with a nontrivial band gap of up to 92.5 meV. On the other hand, Se- and S-based MX2 undergoes the topological phase transition from the QSH effect to the quantum anomalous Hall (QAH) effect and into trivial phases with increasing light intensity. From a general perspective, our work brings further insight into non-equilibrium topological systems.

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