中国物理B ›› 2018, Vol. 27 ›› Issue (8): 87307-087307.doi: 10.1088/1674-1056/27/8/087307

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Multi-carrier transport in ZrTe5 film

Fangdong Tang(汤方栋), Peipei Wang(王培培), Peng Wang(王鹏), Yuan Gan(甘远), Le Wang(王乐), Wei Zhang(张威), Liyuan Zhang(张立源)   

  1. 1 Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Natual Materials & Micro-nano Devices, Renmin University of China, Beijing 100872, China;
    2 Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
  • 收稿日期:2018-04-10 修回日期:2018-06-01 出版日期:2018-08-05 发布日期:2018-08-05
  • 通讯作者: Le Wang E-mail:le.wang@ruc.edu.cn
  • 基金资助:

    Project supported by Guangdong Innovative and Entrepreneurial Research Team Program (Grant No. 2016ZT06D348) and Shenzhen Peacock Program (Grant No. KQTD2016022619565991).

Multi-carrier transport in ZrTe5 film

Fangdong Tang(汤方栋)1,2, Peipei Wang(王培培)2, Peng Wang(王鹏)2, Yuan Gan(甘远)2, Le Wang(王乐)1, Wei Zhang(张威)1, Liyuan Zhang(张立源)2   

  1. 1 Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Natual Materials & Micro-nano Devices, Renmin University of China, Beijing 100872, China;
    2 Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
  • Received:2018-04-10 Revised:2018-06-01 Online:2018-08-05 Published:2018-08-05
  • Contact: Le Wang E-mail:le.wang@ruc.edu.cn
  • Supported by:

    Project supported by Guangdong Innovative and Entrepreneurial Research Team Program (Grant No. 2016ZT06D348) and Shenzhen Peacock Program (Grant No. KQTD2016022619565991).

摘要:

Single-layered zirconium pentatelluride (ZrTe5) has been predicted to be a large-gap two-dimensional (2D) topological insulator, which has attracted particular attention in topological phase transitions and potential device applications. Herein, we investigated the transport properties in ZrTe5 films as a function of thickness, ranging from a few nm to several hundred nm. We determined that the temperature of the resistivity anomaly peak (Tp) tends to increase as the thickness decreases. Moreover, at a critical thickness of~40 nm, the dominating carriers in the films change from n-type to p-type. A comprehensive investigation of Shubnikov-de Hass (SdH) oscillations and Hall resistance at variable temperatures revealed a multi-carrier transport tendency in the thin films. We determined the carrier densities and mobilities of two majority carriers using the simplified two-carrier model. The electron carriers can be attributed to the Dirac band with a non-trivial Berry phase π, while the hole carriers may originate from surface chemical reaction or unintentional doping during the microfabrication process. It is necessary to encapsulate the ZrTe5 film in an inert or vacuum environment to potentially achieve a substantial improvement in device quality.

关键词: multi-carrier transport, ZrTe5 film, thickness-dependence, gate-dependence

Abstract:

Single-layered zirconium pentatelluride (ZrTe5) has been predicted to be a large-gap two-dimensional (2D) topological insulator, which has attracted particular attention in topological phase transitions and potential device applications. Herein, we investigated the transport properties in ZrTe5 films as a function of thickness, ranging from a few nm to several hundred nm. We determined that the temperature of the resistivity anomaly peak (Tp) tends to increase as the thickness decreases. Moreover, at a critical thickness of~40 nm, the dominating carriers in the films change from n-type to p-type. A comprehensive investigation of Shubnikov-de Hass (SdH) oscillations and Hall resistance at variable temperatures revealed a multi-carrier transport tendency in the thin films. We determined the carrier densities and mobilities of two majority carriers using the simplified two-carrier model. The electron carriers can be attributed to the Dirac band with a non-trivial Berry phase π, while the hole carriers may originate from surface chemical reaction or unintentional doping during the microfabrication process. It is necessary to encapsulate the ZrTe5 film in an inert or vacuum environment to potentially achieve a substantial improvement in device quality.

Key words: multi-carrier transport, ZrTe5 film, thickness-dependence, gate-dependence

中图分类号:  (Electronic transport phenomena in thin films)

  • 73.50.-h
73.23.-b (Electronic transport in mesoscopic systems) 73.63.-b (Electronic transport in nanoscale materials and structures)