Polarized Raman Study of NiPS3: Domain Structures and Interlayer Interactions in Twisted Homostructures
- 발행기관 서강대학교 일반대학원
- 지도교수 정현식
- 발행년도 2026
- 학위수여년월 2026. 2
- 학위명 박사
- 학과 및 전공 일반대학원 물리학과
- 실제URI http://www.dcollection.net/handler/sogang/000000082444
- UCI I804:11029-000000082444
- 본문언어 영어
- 저작권 논문은 저작권에 의해 보호받습니다.
초록(요약문)
Nickel phosphorus trisulfide (NiPS₃) is a van der Waals antiferromagnet exhibiting intricate spin and lattice dynamics. Using polarization-resolved Raman spectroscopy, we explored magnon excitations, domain structures, and interlayer coupling in NiPS₃. Low-energy magnons (~1 meV) are directly observed even in bilayers, and their polarization dependence is correlated with distinct spin-exchange pathways. In few-layer NiPS₃, three domain orientations separated by 120° are identified by the polarization dependence of Raman intensity of the phonon at ~178, 180 cm–1. The polarized Raman results are compared with transmission electron microscopy analysis to determine the nature of these domains. Furthermore, in 3L+3L NiPS₃ homostructures, modified phonon and magnon responses revealed tunable interlayer magnetic coupling. These findings demonstrate the power of Raman spectroscopy in probing spin–lattice interactions and domain phenomena in two-dimensional antiferromagnets.
more목차
I. Introduction 14
A. XXZ-type antiferromagnet NiPS₃ 16
(1) Structure and magnetism of TMPS3 16
(2) Magnetism of XXZ type NiPS₃ 18
B. Raman Spectroscopy 28
(1) Principles of Raman Spectroscopy [41-43] 28
(2) Macroscopic theory of inelastic light scattering [41] 34
(3) Raman scattering by magnons [41, 44, 45] 41
II. Experimental 49
A. Sample Preparation 49
B. Raman measurements. 51
III. Results and Discussion 58
A. Polarized Raman of magnon of NiPS₃ [28] 58
(1) Magnon signal on bulk sample 58
(2) Theoretical Analysis on Raman Selection Rule 65
(3) Raman spectroscopy on few-layer NiPS3 71
(4) Inelastic Neutron Scattering Analysis 76
B. Domain structure of NiPS₃ 84
(1) Polarized Raman on few-layer NiPS₃ 84
(2) TEM results 87
(3) Temperature dependence of Raman spectrum 92
(4) Thermal-cycle invariance of P2 polarization in 3L NiPS₃ 97
(5) Polarized Raman on thicker NiPS₃ 99
C. 3L+3L homostructure of NiPS₃ 102
(1) Polarized Raman on 90° and –90° 3+3L NiPS₃ 102
(2) Temperature dependent Raman on 90° 3L+3L NiPS₃ 107
(3) Polarized Raman on 0° and 180° 3+3L NiPS₃ 110
IV. Summary 114
V. References 116
