论文标题
单层WSE $ _2 $中相边界处的拓扑电子状态和热电传输：有效的汉密尔顿理论
Topological electronic states and thermoelectric transport at phase boundaries in single-layer WSe$_2$: An effective Hamiltonian theory
论文作者
论文摘要
扭曲的八面体1T $^\ prime $相位中的单层过渡金属二分裂元化具有较大的体积带隙和无间隙边界状态，这是持续寻求拓扑电子设备的资产。在单层钨丝（WSE $ _2 $）中，已经在有序的界面上观察到边界状态在1t $^\ prime $和半导体（1H）阶段之间。本文提出了一个有效的4波段理论，以单层WSE $ _2 $中的边界状态，描述了Kramers对差距的一对以及在1T $^\ prime $相位的传导和价频段上的频谱终止点的行为。光谱终止点决定了相边界处弹道电导和热电器的温度和化学势依赖性。值得注意的是，热电器显示出双极行为，改变了1T $^\ prime $ -WSE $ _2 $的带隙中的标志，并反映其粒子孔不对称。该理论在单层WSE $ _2 $中建立了散装带结构与弹道边界传输之间的联系，并且适用于一系列相关的拓扑材料。
Monolayer transition metal dichalcogenides in the distorted octahedral 1T$^\prime$ phase exhibit a large bulk bandgap and gapless boundary states, which is an asset in the ongoing quest for topological electronics. In single-layer tungsten diselenide (WSe$_2$), the boundary states have been observed at well ordered interfaces between 1T$^\prime$ and semiconducting (1H) phases. This paper proposes an effective 4-band theory for the boundary states in single-layer WSe$_2$,describing a Kramers pair of in-gap states as well as the behaviour at the spectrum termination points on the conduction and valence bands of the 1T$^\prime$ phase. The spectrum termination points determine the temperature and chemical potential dependences of the ballistic conductance and thermopower at the phase boundary. Notably, the thermopower shows an ambipolar behaviour, changing the sign in the bandgap of the 1T$^\prime$ - WSe$_2$ and reflecting its particle-hole asymmetry. The theory establishes a link between the bulk band structure and ballistic boundary transport in single-layer WSe$_2$ and is applicable to a range of related topological materials.
