Abstract
EuCd2As2 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 EuCd2As2 crystals in previous experiments prevent direct identification of the semimetal hypothesis.Here,we present a comprehensive magneto-transport study of high-quality EuCd2As2 crystals with ultralow bulk carrier density(1013 cm-3).In contrast to the general expectation of a Weyl semimetal phase,EuCd2As2 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 EuCd2As2 and put a strong constraint on the underlying mechanism of anomalous transport properties in this system.
基金项目
国家重点研发计划(2022YFA1405700)
国家自然科学基金(12174069)
国家自然科学基金(92365104)
Shuguang Program supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission()
Double First-Class Initiative Fund of Shanghai Tech University()
open project from Beijing National Laboratory for Condensed Matter Physics()
国家重点研发计划(2022YFA1602603)
国家自然科学基金(12122411)
国家自然科学基金(12274090)
上海市自然科学基金(22ZR1406300)
万方数据