Probing magnetic anisotropy of Cr-intercalated CrTe₂ ultra-thin film: DFT-based spin-orbit torque method

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/97794

Title:	Probing magnetic anisotropy of Cr-intercalated CrTe₂ ultra-thin film: DFT-based spin-orbit torque method
Authors:	曾宥勝;Tseng, Yu-Sheng
Contributors:	物理學系
Keywords:	磁異向性;自旋軌道扭矩;二維材料;magnetic anisotropy energy;spin-orbit torque;two-dimensional materials
Date:	2025-07-22
Issue Date:	2025-10-17 11:54:32 (UTC+8)
Publisher:	國立中央大學
Abstract:	二維凡得瓦鐵磁材料其在磁性裝置的電控制方面具有提升使用能量效率的潛力，大多數層狀磁性材料可分為兩大類，過渡金屬鹵化物與過渡金屬硫族化物。對於CrₓTeᵧ系統，其鐵磁相變溫度可超過室溫，有實際應用的潛力，然而，其磁矩普遍認為主要由Cr所主導，而磁性異向性則主要來自Te，這是由於Te本身具有比Cr強烈的自旋軌道耦合強度，磁矩則主要由Cr貢獻，磁矩跟磁異向性間的來源自不同元素，其關聯仍不清楚。在本研究中，我們採用第一原理計算，確定單層、雙層、CrTe₂及CrTe₂–Crₓ–CrTe₂結構的磁性基態後，我們開發的新型自旋軌道磁矩計算，被使用來預測其磁性異向性，並解析Cr與Te之間的交互作用。我們的結果成功地說明了來自Te的自旋軌道磁矩是自旋累積晶格場傳遞至Cr，此外，我們提出自旋累積流的分析方式，可用在拆解摻雜結構中不同層的自旋軌道耦合能量貢獻，這是傳統二階微擾理論所無法處理的。;Intensive research on two-dimensional magnetic materials has emerged due to their potential to improve energy efficiency in the electrical control of magnetic devices. Most layered magnetic materials fall into two main families, transition metal halides and transition metal chalcogenides. For CrxTey, the magnetic moment is believed to be dominated by Cr, whereas the magnetic anisotropy is primarily contributed by Te due to its strong spin-orbit coupling strength. The relationship between spin-orbit coupling and the magnetic moment carrier remains an open question. In this study, we employ first-principles calculations to determine the magnetic ground states of monolayer, bilayer CrTe2, and CrTe2-Crx-CrTe2 structures. Our newly developed spin-orbit torque method is applied to predict their magnetic anisotropies and to elucidate the interaction between Cr and Te. Our results successfully explain how the spin-orbit torque originating from Te is transferred to Cr by spin accumulation through crystal field. Furthermore, we develop a spin accumulation flow analysis to decompose the spin-orbit coupling energy contributions toward different layers in the intercalated structures which cannot be addressed by conventional second-order perturbation theory.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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