论文标题
通过Janus杂质探测八度隐藏订单
Probing octupolar hidden order via Janus impurities
论文作者
论文摘要
带有非kramer二倍的量子材料是实现多极隐藏订单的引人入胜的场所。破坏点组对称性的杂质探针，例如植入的兆粒或替代杂质，将非kramers变性分开，并在这种系统中表现出janus面的影响：它们可以破坏他们寻求探测的顺序。在这里，我们探索了Cubic Osmate双钙棍的这种双重性，这是与四甲状化州竞争的异国情调的$ D $ D $ - 轨道八度命令的候选者。使用{\ it ab intib}计算，Landau理论和蒙特卡洛模拟，我们表明Janus杂质会诱导局部应变场，成核二次极性水坑并抑制八度$ T_C $。同时，应变将非kramer Doublet与激发的磁性三重态混合在一起，从而产生寄生偶极矩，从而直接暴露隐藏的八极极阶参数。我们的工作在最近的杂质核磁共振（NMR）实验中揭开了Janus二元性，这对在不同的多极材料中发现隐藏的顺序具有重要意义。
Quantum materials with non-Kramers doublets are a fascinating venue to realize multipolar hidden orders. Impurity probes which break point group symmetries, such as implanted muons or substitutional impurities, split the non-Kramers degeneracy and exhibit a Janus-faced influence in such systems: they can destroy the very order they seek to probe. Here, we explore this duality in cubic osmate double perovskites which are candidates for exotic $d$-orbital octupolar order competing with quadrupolar states. Using {\it ab initio} computations, Landau theory, and Monte Carlo simulations, we show that Janus impurities induce local strain fields, nucleating quadrupolar puddles and suppressing the octupolar $T_c$. At the same time, strains mix the non-Kramers doublet with an excited magnetic triplet, creating parasitic dipole moments which directly expose the hidden octupolar order parameter. Our work unravels this Janus duality in recent impurity nuclear magnetic resonance (NMR) experiments, with important implications for uncovering hidden order in diverse multipolar materials.
