Multi-carrier transport in ZrTe5 film

• 来源期刊: 中国物理B（英文版）
• 关键词: multi-carrier transport ZrTe5 film thickness-dependence gate-dependence
• 年，卷（期）: 2018,（8）
• 页码范围: 508-514
• 页数: 7页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/8/087307

摘要

Single-layered zirconium pentatelluride (ZrTe5) has been predicted to be a large-gap two-dimensional (2D) topolog-ical 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 car-riers using the simplified two-carrier model. The electron carriers can be attributed to the Dirac band with a non-trivial Berry phaseπ, 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.