非共线磁体上交换关联泛函的测试：Mn₃Ir、Mn₃Ge、NiS₂与YMnO₃
A test drive for exchange-correlation functionals on noncollinear magnets: Mn$_3$Ir, Mn$_3$Ge, NiS$_2$, and YMnO$_3$
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中文总结 AI 辅助
本研究测试了非共线SCDFT泛函与SDFT泛函在非共线磁体上的表现，发现仅SCDFT泛函可重现NiS₂实验基态自旋结构，且计算成本与标准半局域近似相当，体现了SCDFT捕捉非共线物理的实用性。
中文摘要 AI 辅助
非共线磁体的第一性原理描述颇具挑战性，而真正非共线交换关联近似的实际表现大多未经过测试。自旋电流密度泛函理论（SCDFT）允许受局域U(1)×SU(2)规范不变性约束的非共线近似，这一精确条件在限制更严格的自旋密度泛函理论（SDFT）框架中无法实现。我们使用维也纳从头算模拟包（VASP），将两种最新开发的非共线SCDFT泛函（NCMSCAN与LFNCBR89-NCCS），与四种常见泛函（PZ、PW92、PBE、SCAN）的局域共线SDFT扩展，在多个非共线d电子体系上进行对比。关键发现是，在所有测试的泛函中，仅SCDFT泛函能重现NiS₂实验基态的自旋结构，且其计算成本与标准半局域近似相当。不过，这两种SCDFT泛函在平衡体积、带隙及局域磁矩上存在差异。总体而言，本研究表明SCDFT在捕捉非共线物理方面具有实用性，所测试的近似方法也体现了这一点。
英文摘要
A first-principles description of noncollinear magnets is challenging, and the practical behavior of genuinely noncollinear exchange-correlation approximations is largely untested. Spin-current density-functional theory (SCDFT) admits noncollinear approximations constrained by local U(1)$\times$SU(2) gauge invariance, an exact condition unavailable in the more restrictive framework of spin-DFT (SDFT). Using the Vienna ab initio simulation package (VASP), we compare two recently developed noncollinear SCDFT functionals, NCMSCAN and LFNCBR89-NCCS, against locally collinear SDFT extensions of four common functionals (PZ, PW92, PBE, and SCAN) for several noncollinear $d$-electron systems. The key finding is that among all tested functionals, only the SCDFT functionals recover the spin texture of the experimental ground state of NiS$_2$, and they do so at a cost comparable to standard semi-local approximations. Yet the two SCDFT functionals differ in equilibrium volumes, band gaps, and on-site magnetic moments. Overall, this survey illustrates the usefulness of SCDFT in capturing noncollinear physics with the tested approximations.
