Absence of metallicity and bias-dependent resistivity in low-carrier-density EuCd_(2)As_(2)  

作　　者：Yuxiang Wang Jianwen Ma Jian Yuan Wenbin Wu Yong Zhang Yicheng Mou Jiaming Gu Peihong Cheng Wu Shi Xiang Yuan Jinglei Zhang Yanfeng Guo Cheng Zhang 

机构地区：[1]State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing,Fudan University,Shanghai 200433,China [2]School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China [3]State Key Laboratory of Precision Spectroscopy,East China Normal University,Shanghai 200241,China [4]Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions,High Magnetic Field Laboratory of the Chinese Academy of Sciences,Hefei 230031,China [5]School of Physics and Electronic Science,East China Normal University,Shanghai 200241,China [6]Zhangjiang Fudan International Innovation Center,Fudan University,Shanghai 201210,China [7]ShanghaiTech Laboratory for Topological Physics,Shanghai 201210,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第4期119-125,共7页中国科学：物理学、力学、天文学（英文版）

基　　金：sponsored by the National Key R&D Program of China(Grant No.2022YFA1405700);the National Natural Science Foundation of China(Grant Nos.12174069,and 92365104);the Shuguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission;supported by the Double First-Class Initiative Fund of Shanghai Tech University;the open project from Beijing National Laboratory for Condensed Matter Physics;supported by the National Key R&D Program of China(Grant No.2022YFA1602603);the National Natural Science Foundation of China(Grant No.12122411);supported by the National Natural Science Foundation of China(Grant No.12274090);the Natural Science Foundation of Shanghai(Grant No.22ZR1406300)。

摘　　要：EuCd_(2)As_(2)was theoretically predicted to be a minimal model of Weyl semimetals with a single pair of Weyl points in the ferromagnet state.However,the heavily p-doped Eu Cd_(2)As_(2)crystals in previous experiments prevent direct identification of the semimetal hypothesis.Here,we present a comprehensive magneto-transport study of high-quality Eu Cd_(2)As_(2)crystals with ultralow bulk carrier density(10^(13)cm^(-3)).In contrast to the general expectation of a Weyl semimetal phase,Eu Cd_(2)As_(2)shows insulating behavior in both antiferromagnetic and ferromagnetic states as well as surface-dominated conduction from band bending.Moreover,the application of a dc bias current can dramatically modulate the resistance by over one order of magnitude,and induce a periodic resistance oscillation due to the geometric resonance.Such nonlinear transport results from the high nonequilibrium state induced by an electrical field near the band edge.Our results suggest an insulating phase in Eu Cd_(2)As_(2)and put a strong constraint on the underlying mechanism of anomalous transport properties in this system.

关 键 词：magnetic Weyl semimetal quantum transport Hall effect nonlinear resistivity 

分 类 号：O469[理学—凝聚态物理]