Low-frequency Raman spectroscopic analysis of CrSBr
- 주제(키워드) CrSBr , low frequency raman , polarized raman
- 발행기관 서강대학교 일반대학원
- 지도교수 정현식
- 발행년도 2026
- 학위수여년월 2026. 2
- 학위명 석사
- 학과 및 전공 일반대학원 물리학과
- 실제URI http://www.dcollection.net/handler/sogang/000000082423
- UCI I804:11029-000000082423
- 본문언어 한국어
- 저작권 논문은 저작권에 의해 보호받습니다.
초록(요약문)
Chromium Sulfur Bromide (CrSBr) is a layered van der Waals magnetic semiconductor which is an A-type antiferromagnetic (AFM) order with its magnetic easy axis aligned along the crystallographic b direction. Owing to its strong in-plane mass anisotropy and electron-hole effective mass, it has a quasi-1D characteristic. And it exhibits a relatively high Néel temperature, TN, and crystallizes in an orthorhombic structure with space group 59 (Pmmn) and point group D2h. Although its crystal structure and electromagnetic properties have been extensively studied, the low frequency Raman spectra of CrSBr has not been investigated. In this work, we therefore focuse on the low frequency Raman spectra of CrSBr. We fabricated the mono and few layer CrSbr samples on the 90nm SiO2/Si substrate by using the mechanical exfoliation method. We define the magnetic easy axis of CrSBr with the polarized Raman spectroscopy. Among the excitation wavelengths tested, 2.33 eV proved most effective for resolving both low and high frequency Raman modes. We observed the low frequency Raman signals near 10 cm-1 in both a and b axis configurations, with significantly stronger intenstiy along b direction. Temperature dependent Raman measurements reveal that these modes gradually broaden and weakened upon cooling. Also, for the high frequency Raman spectra we observed that near the TN, 𝐴𝑔 mode broadening along the b axis. These results provide new insights into the phonon and magnetic fluctuation dynamics in CrSBr as well as their excitation energy dependent revealed by low frequency Raman spectroscopy
more목차
I. Introduction 1
II. Theory 3
A.Chromium Sulfur Bromide (CrSBr) 3
B. Raman Spectroscopy 5
III. Experiments 14
A. Sample Preparation. 14
B. Polarized Raman Spectroscopy 14
IV. Results & Discussion 18
A.Determination of Magnetic easy axis and layers 18
B. Temperature dependent on CrSBr 24
V. Summary 36
VI. References 37
