Determination of the surface states from the ultrafast electronic states in a thermoelectric material

• 作者: Tongyao Wu Hongyuan Wang Yuanyuan Yang Shaofeng Duan Chaozhi Huang Tianwei Tang Yanfeng Guo Weidong Luo Wentao Zhang
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2022,（2）
• 所属期刊栏目: RAPID COMMUNICATION
• 页码范围: 166-171
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/ac373c

摘要

We reveal the electronic structure in YbCd2Sb2,a thermoelectric material,by angle-resolved photoemission spec-troscopy (ARPES) and time-resolved ARPES (trARPES).Specifically,three bulk bands at the vicinity of the Fermi level are evidenced near the Brillouin zone center,consistent with the density functional theory (DFT) calculation.It is inter-esting that the spin-unpolarized bulk bands respond unexpectedly to right-and left-handed circularly polarized probe.In addition,a hole band of surface states,which is not sensitive to the polarization of the probe beam and is not expected from the DFT calculation,is identified.We find that the non-equilibrium quasiparticle recovery rate is much smaller in the surface states than that of the bulk states.Our results demonstrate that the surface states can be distinguished from the bulk ones from a view of time scale in the nonequilibrium physics.