通过平坦磁能谱解决RuO2的磁基态争议
Resolving the Magnetic Ground-State Controversy in RuO2 through A Flat Magnetic Energy Landscape
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中文总结 AI 辅助
本文通过开发广义环境依赖自旋-晶格框架，结合机器学习与蒙特卡洛模拟，解释了RuO2磁基态的实验争议，揭示其平坦磁能谱的特性及材料微扰选择磁基态的机制。
中文摘要 AI 辅助
金红石型RuO2是反常磁性（altermagnetism）的重要候选材料，但其磁基态仍存在高度争议，实验报道其为非磁性态或反常磁性有序态。本文开发了一种广义的环境依赖自旋-晶格框架，该框架统一了局域海森堡交换、通过朗道自旋涨落实现的巡游斯托纳磁性，以及自旋轨道耦合介导的自旋-晶格相互作用。该框架基于高通量第一性原理数据库，通过机器学习参数化，并经大规模蒙特卡洛模拟求解，结果显示RuO2存在异常平坦的磁能谱，其中非磁性态与多种反常磁性构型几乎简并。研究发现，以本征缺陷为代表的材料微扰主要通过改变局域海森堡交换来选择不同的磁基态，而微扰诱导的巡游斯托纳极化则提供了重要的次要贡献。自旋轨道耦合控制奈尔矢量的取向和稳定性，但不决定长程磁有序的出现。这些结果为相互矛盾的实验观测提供了统一解释，并建立了通用的微观框架，用于理解材料微扰如何在具有近平坦磁能谱的体系中选择竞争的磁基态。
英文摘要
Rutile RuO2 is a prominent candidate for altermagnetism, yet its magnetic ground state remains highly controversial, with experiments reporting either a nonmagnetic state or altermagnetic order. Here, we develop a generalized environment-dependent spin-lattice framework that unifies localized Heisenberg exchange, itinerant Stoner magnetism via Landau spin fluctuations, and spin-orbit-coupling-mediated spin-lattice interactions. Parameterized from a high-throughput first-principles database using machine-learning and solved by large-scale Monte Carlo simulations, the framework reveals an exceptionally flat magnetic energy landscape in RuO2, where the nonmagnetic state lies nearly degenerate with multiple altermagnetic configurations. We find that material perturbations, exemplified by intrinsic defects, select distinct magnetic ground states primarily by modifying the localized Heisenberg exchange, with perturbation-induced itinerant Stoner polarization provides an essential secondary contribution. Spin-orbit coupling controls the orientation and stability of the Néel vector, but does not determine the emergence of long-range magnetic order. These results provide a unified explanation for the conflicting experimental observations and establish a general microscopic framework for understanding how material perturbations select competing magnetic ground states in systems with nearly flat magnetic energy landscapes.
发表机构
- Key Laboratory of Material Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education（激光、离子束和电子束材料改性重点实验室（大连理工大学），教育部）
- School of Physics, South China Normal University（华南师范大学物理学院）
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area（粤港澳大湾区量子科学中心）
机构由 AI 辅助整理，请以论文原文为准。
