AI 中文总结
本研究基于第一性原理模拟，揭示Cr掺杂FeSb₂呈局域无序自旋补偿态、Co掺杂FeSb₂呈交替磁性，确立了研究金属交替磁体的模拟方案。
AI 中文摘要
近期实验报道表明，窄带非磁性半导体FeSb₂可通过Co掺杂（Co₀.₁₅Fe₀.₈₅Sb₂）转变为交替磁性金属，或通过Cr掺杂（Cr₀.₁₅Fe₀.₈₅Sb₂）转变为磁无序或短程有序态。本文基于第一性原理，结合哈伯德增强密度泛函理论（DFT+U）与Romeo基态搜索算法，探究这些掺杂体系的能量态势与磁态。在已确立的虚拟晶体近似（VCA）框架内，研究显示Romeo算法可找到多种非平凡磁态，为超胞掺杂的针对性显式模拟提供依据。基于这些发现，本文讨论了VCA-Romeo方法与显式掺杂超胞方法的优势及局限，以及二者如何协同使用。总体而言，模拟结果表明Cr掺杂体系的基态为局域无序自旋补偿（LDSC）构型，形式上与Néel的L型完全补偿亚铁磁兼容；而Co掺杂体系的基态为交替磁性（AFMo）。本研究阐明了磁性合金的近似模拟与显式模拟如何相互提供信息，并建立了研究候选金属交替磁体的方案。
英文摘要
Recent experimental reports suggest that the narrow-gap nonmagnetic semiconductor FeSb$_2$ can be transformed into an altermagnetic metal through Co doping (Co$_{0.15}$Fe$_{0.85}$Sb$_2$), or into a magnetically disordered or short-range-ordered state through Cr doping (Cr$_{0.15}$Fe$_{0.85}$Sb$_2$). Here we explore the energy landscape and magnetic states of these doped systems from first principles, relying on Hubbard-augmented density-functional theory (DFT+U) combined with the Romeo ground-state search algorithm. Within the established virtual-crystal approximation (VCA), we show that \texttt{Romeo} finds several non-trivial magnetic states, which inform targeted explicit simulations of doping in supercells. We rely on these findings to discuss strengths and limitations of the VCA-Romeo approach versus the explicit-doping supercell approach, and how they can be used in synergy. Overall, our simulations suggest that the ground state of the Cr-doped system is a Locally Disordered Spin-Compensated (LDSC) configuration, formally compatible with Néel's L-type fully compensated ferrimagnetism, whereas the ground state of the Co-doped system is found to be altermagnetic (AFMo). This work shows how approximate and explicit simulations of magnetic alloys can be mutually informative, and establishes a protocol for studying candidate metallic altermagnets.
Comments5 pages and 5 figures (main), 8 pages and 11 figures (supplementary)
