Nonmagnetic Ground States and a Possible Quadrupolar Phase in 4d and 5d Lacunar Spinel Selenides GaM4Se8 (M = Nb, Ta)
Nonmagnetic Ground States and a Possible Quadrupolar Phase in 4d and 5d Lacunar Spinel Selenides GaM4Se8 (M = Nb, Ta)
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DOI：
10.1103/physrevlett.124.227202
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发表时间：
2020-06-04
影响因子：
8.6
通讯作者：
Kindo, Koichi
中科院分区：
文献类型：
--
作者：
Ishikawa, Hajime;Yajima, Takeshi;Kindo, Koichi
研究了J（eff）= 3/2 Mott分子绝缘体候选材料立方尖晶石硒化物GaM_4Se_8（M = Nb，Ta）的结构和磁性。与仅自旋值相比，有效磁矩减小，表明存在相当大的自旋-轨道耦合。GaNb_4Se_8和GaTa_4Se_8分别表现出正交和四方结构的基态相变，其对高达至少60 T的磁场具有鲁棒性。在GaNb_4Se_8中观察到一个立方相转变，这表明在J（eff）= 3/2的Mott绝缘体中存在理论预测的四极有序相。
Structural and magnetic properties of cubic spinel selenides GaM4Se8 (M = Nb, Ta), which are candidates for the molecular J(eff) = 3/2 Mott insulators, are investigated. The effective magnetic moments are reduced compared to the spin only value, indicating the presence of sizable spin-orbit coupling. GaNb4Se8 and GaTa4Se8 exhibit phase transitions into the nonmagnetic ground states with orthorhombic and tetragonal structures, respectively, which are robust against magnetic field up to at least 60 T. A cubic-cubic phase transition is observed in GaNb4Se8 preceding the magnetic transition, suggesting the existence of a quadrupolar-ordered phase theoretically predicted in the J(eff) = 3/2 Mott insulator.