论文标题
面部为中心的立方晶格中的四杆部分部分订单和三重$ q $状态
Quadrupole partial orders and triple-$q$ states on the face-centered cubic lattice
论文作者
论文摘要
我们研究$γ_3$四螺杆订单以面部为中心的立方晶格。立方对称下的$γ_3$四极力矩在统一($ q = 0 $)扇区中具有独特的立方体不变,而x点$ q =(2π,0,0),(0,2π,0)$和$(0,0,0,2π)$ q =(2π,0,0)$ q =(2π,0,0)。这种立方各向异性与各向异性四极核 - Quadrupole相互作用之间的竞争会对基态和有限温度下的相图产生巨大影响。我们展示了有关模型构建及其属性的详细信息,相图以及我们先前字母中报告的各种三重$ q $四螺旋体订单的机制[J.物理。 Soc。 JPN。 90,43701(2021),Arxiv:2102.06346]。通过使用平均场方法,我们分析了一个四极杆交换模型,该模型由晶体 - 晶体场方案组成,其地面$γ_3$ non-kramers doublet和激发的Singlet Singlet $γ_1$ state。我们在四个公共平均场近似中发现了各种三重$ q $订单。与单$ Q $订单相比,在更高的过渡温度下,在广泛的参数空间中稳定了一些部分订单。随着降低温度,这些部分阶的相转变为进一步的对称性损坏相,在此期间,在以前无序的位点出现了非消失的四极矩矩。平均场近似中获得的阶段通过现象学兰道理论进行了研究,该理论清楚地表明,立方体不变剂在稳定三重$ q $状态方面起着重要作用。我们还讨论了它对几种F-和D电子化合物的最新实验的影响。
We study $Γ_3$ quadrupole orders in a face-centered cubic lattice. The $Γ_3$ quadrupole moments under cubic symmetry possess a unique cubic invariant in their free energy in the uniform ($q=0$) sector and the triple-q sector for the X points $q=(2π,0,0),(0,2π,0)$, and $(0,0,2π)$. Competition between this cubic anisotropy and anisotropic quadrupole-quadrupole interactions causes a drastic impact on the phase diagram both in the ground state and at finite temperatures. We show details about the model construction and its properties, the phase diagram, and the mechanism of the various triple-$q$ quadrupole orders reported in our preceding letter [J. Phys. Soc. Jpn. 90, 43701 (2021), arXiv:2102.06346]. By using a mean-field approach, we analyze a quadrupole exchange model that consists of a crystalline-electric field scheme with the ground-state $Γ_3$ non-Kramers doublet and the excited singlet $Γ_1$ state. We find various triple-$q$ orders in the four-sublattice mean-field approximation. A few partial orders of quadrupoles are stabilized in a wide range of parameter space at a higher transition temperature than single-$q$ orders. With lowering the temperature, these partial orders undergo phase transitions into further symmetry broken phases in which nonvanishing quadrupole moments emerge at previously disordered sites. The obtained phases in the mean-field approximation are investigated by a phenomenological Landau theory, which clearly shows that the cubic invariant plays an important role for stabilizing the triple-$q$ states. We also discuss its implications for recent experiments in a few f- and d-electron compounds.