Comparative Raman spectroscopy of magnetic topological material EuCd2X2(X = P, As)

Yuhan Du; Ju Chen; Wenbin Wu; Zeping Shi; Xianghao Meng; Cheng Zhang; Shijing Gong; Junhao Chu; Xiang Yuan

doi:10.1088/1361-648X/ac5d1b

Comparative Raman spectroscopy of magnetic topological material EuCd₂X₂(X = P, As)

J Phys Condens Matter. 2022 Mar 30;34(22). doi: 10.1088/1361-648X/ac5d1b.

Authors

Yuhan Du¹, Ju Chen², Wenbin Wu¹, Zeping Shi¹, Xianghao Meng¹, Cheng Zhang³, Shijing Gong², Junhao Chu^{2

4

5}, Xiang Yuan^{1

2}

Affiliations

¹ State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, People's Republic of China.
² Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China.
³ Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, People's Republic of China.
⁴ Institute of Optoelectronics, Fudan University, Shanghai 200433, People's Republic of China.
⁵ Key Laboratory of Polar Materials and Devices (Ministry of Education), East China Normal University, Shanghai 200241, People's Republic of China.

PMID: 35362463
DOI: 10.1088/1361-648X/ac5d1b

Abstract

EuCd₂X₂(X = P, As) is a new class of magnetic topological materials discovered recently. The electronic structure and the band topology are intimately coupled with its magnetism, giving rise to interesting properties such as spin fluctuation and colossal magnetoresistance. Phonon excitation can contribute to the quasi-particle response of the topological matters through spin-lattice and electron-phonon coupling. However, the phonon properties of this material family remain unexplored. Here we report a comparative study of Raman-active vibration modes in EuCd₂X₂(X = P, As) by means of angle-resolved, temperature-resolved, and magnetic-field-resolved Raman spectroscopy together with the first-principle calculations and Raman tensor analysis. The phonon properties can be tuned by chemical potential and temperature within the material family. All the phonon modes are softened with increased chemical pressure by replacing P with As. Angle-resolved polarized Raman spectroscopy reveals the configuration-sensitive Raman activity and the isotropic intensity response. In addition, the magneto-Raman spectrum indicates the stability of Raman-active vibration modes against the magnetic field at room temperature. Our work sheds light on the phonon dynamics of magnetic topological matters, which are potentially coupled with the topological charge and spin excitation.

Keywords: Raman spectroscopy; Weyl semimetal; magnetic topological phase.