Generation of Fabry–Pérot oscillations and Dirac state in two-dimensional topological insulators by gate voltage  

作　　者：徐斌 李饶 傅华华 

机构地区：[1]Department of Mathematics and Information Sciences, North China university of Water Resources and Electric Power, Zhengzhou 450011, China [2]Henan Mechanical and Electrical Vocational College, Zhengzhou 451191, China [3]School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China

出　　处：《Chinese Physics B》2017年第5期352-356,共5页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.U1404108,11104072,and 10947162);Henan Foundation and Frontier Technology Research Program of China(Grant No.162300410056)

摘　　要：We investigate electron transport through Hg Te ribbons embedded by strip-shape gate voltage through using a nonequilibrium Green function technique. The numerical calculations show that as the gate voltage is increased, an edgerelated state in the valence band structure of the system shifts upwards, then hangs inside the band gap and merges into the conduction band finally. It is interesting that as the gate voltage is increased continuously, another edge-related state in the valence band also shifts upwards in the small-k region and contacts the previous one to form a Dirac cone in the band structure. Meanwhile in this process, the conductance spectrum displays as multiple resonance peaks characterized by some strong antiresonance valleys in the band gap, then behaves as Fabry–P＇erot oscillations and finally develops into a nearly perfect quantum plateau with a value of 2e^2/h. These results give a physical picture to understand the formation process of the Dirac state driven by the gate voltage and provide a route to achieving particular quantum oscillations of the electronic transport in nanodevices.We investigate electron transport through Hg Te ribbons embedded by strip-shape gate voltage through using a nonequilibrium Green function technique. The numerical calculations show that as the gate voltage is increased, an edgerelated state in the valence band structure of the system shifts upwards, then hangs inside the band gap and merges into the conduction band finally. It is interesting that as the gate voltage is increased continuously, another edge-related state in the valence band also shifts upwards in the small-k region and contacts the previous one to form a Dirac cone in the band structure. Meanwhile in this process, the conductance spectrum displays as multiple resonance peaks characterized by some strong antiresonance valleys in the band gap, then behaves as Fabry–P＇erot oscillations and finally develops into a nearly perfect quantum plateau with a value of 2e^2/h. These results give a physical picture to understand the formation process of the Dirac state driven by the gate voltage and provide a route to achieving particular quantum oscillations of the electronic transport in nanodevices.

关 键 词：topological Dirac picture conductance valence Fabry contacts perfect plateau finally 

分 类 号：O469[理学—凝聚态物理]