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arXiv 1803.03390cond-mat.mes-hallcond-mat.mtrl-sci
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单层MoS2材料的相变和场效应拓扑量子晶体管

Phase Transition and Field Effect Topological Quantum Transistor made of monolayer MoS2

H. Simchi, M. Simchi, M. Fardmanesh, F. M. Peeters

摘要:

采用双带哈密顿模型研究了单层二硫化钼(MoS2)的拓扑相变和拓扑量子场效应晶体管。在不考虑哈密顿量中的二次对角项的情况下,我们证明了该相图包含量子反常霍尔(QAH)、量子自旋霍尔(QSH)和自旋量子反常霍尔效应(SQAH)区域,使得拓扑基尔霍夫定律在平面内满足.通过考虑q^2对角项和包含一个谷,证明了MoS2具有非平凡拓扑,并且谷陈数对于每个自旋都不为零。我们证明了在自旋谷狄拉克质量方程中加入(删除)q^2对角项后,波函数在(或不在)边缘局域化。利用非平衡格林函数方法计算了锯齿形MoS2纳米带的量子电导,并展示了该器件作为场效应拓扑量子晶体管的工作原理。

英文摘要:

We study topological phase transitions and topological quantum field effect transistor in monolayer Molybdenum Disulfide (MoS2) using a two-band Hamiltonian model. Without considering the quadratic (q^2) diagonal term in the Hamiltonian, we show that the phase diagram includes quantum anomalous Hall (QAH), quantum spin Hall (QSH), and spin quantum anomalous Hall effect (SQAH) regions such that the topological Kirchhoff law is satisfied in the plane. By considering the q^2 diagonal term and including one valley, it is shown that MoS2 has a non-trivial topology, and the valley Chern number is non-zero for each spin. We show that the wave function is (is not) localized at the edges when the q^2 diagonal term is added (deleted) to (from) the spin-valley Dirac mass equation. We calculate the quantum conductance of zigzag MoS2 nanoribbons by using the nonequilibrium Green function method and show how this device works as a field effect topological quantum transistor.

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