论文标题
PR 1-2-20 Systems PRT2AL20中的Rkky相互作用和四极顺序的第一原理研究（t = ti，v）
First-principles Study of the RKKY Interaction and the Quadrupole Order in the Pr 1-2-20 systems PrT2Al20 (T=Ti, V)
论文作者
论文摘要
根据第一原理计算，研究了PR 1-2-20系统PRT2AL20系统（t = Ti，v）中的电子状态和四极序。有效的196个轨道模型得出来重现LAT2AL20（t = Ti，v）的第一原理电子结构，而无需PR 4F电子的贡献，这些电子结构被认为是局部局部化的，并被用于计算Ruderman-Kitsel-kasuya-Yosida（Rkky）（Rkky）（Rkky）（Rkky）的相互作用，而四果之间的相互作用是Prions and octupole之间的相互作用。在rkky hamiltonian的随机阶段近似中，在PRTI2AL20的情况下，发现最不同的敏感性是波动向量Q =（0,0,0）的四极，而Q =（pi/a，0，pi/a）在PRV2AL20的情况下是一致的，这两种案例都与实验性观察到了FIRRE，该案例是在实体观察到的FIRRO。抗菌极（AFQ）命令分别。我们还使用均值场近似讨论有序状态，并发现在PRTI2AL20的情况下，一阶相变为O20 FQ顺序，并以微小的不连续性发生如Landau理论所预测的那样。在PRV2AL20的情况下，该系统显示了两个不同的O22 AFQ订单，AFQ-I和AFQ-II，并显示了随后的两个相转换，即从正常到AFQ-I到AFQ-I的两阶转换，以及从AFQ-I到AFQ-II的一阶，可能负责通过特定的热量测量来指责双重过渡。
Electronic states and quadrupole orders in the Pr 1-2-20 systems PrT2Al20 (T=Ti, V) are investigated on the basis of the first-principles calculations. The effective 196 orbital model is derived to reproduce the first-principles electronic structures of LaT2Al20 (T=Ti, V) without contribution from the Pr 4f electrons which are considered to be well localized and is employed to calculate the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between quadrupole and octupole moments of the Pr ions. Within the random phase approximation for the RKKY Hamiltonian, the most divergent susceptibility is found to be the quadrupole one for the wave vector Q = (0,0,0) in the case of PrTi2Al20 while that for Q = (pi/a,0,pi/a) in the case of PrV2Al20 as consistent with experimental observations in the both cases which exhibit the ferro-quadrupole (FQ) and the antiferro-quadrupole (AFQ) orders, respectively. We also discuss the ordered states using the mean-field approximation and find that, in the case of PrTi2Al20, the 1st-order phase transition to the O20 FQ order with a tiny discontinuity takes place as predicted by the Landau theory. In the case of PrV2Al20, the system exhibits two distinct O22 AFQ orders, AFQ-I and AFQ-II, and shows subsequent two phase transitions, the 2nd-order one from normal to AFQ-I and the 1st-order one from AFQ-I to AFQ-II, that may be responsible for the double transitions observed by specific heat measurements.
