K₂RuCl₆中的非磁性J = 0态与自旋轨道激发

Nonmagnetic J=0 State and Spin-Orbit Excitations in K_{2}RuCl_{6}.

作者信息

Takahashi H, Suzuki H, Bertinshaw J, Bette S, Mühle C, Nuss J, Dinnebier R, Yaresko A, Khaliullin G, Gretarsson H, Takayama T, Takagi H, Keimer B

机构信息

Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany.

Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.

出版信息

Phys Rev Lett. 2021 Nov 24;127(22):227201. doi: 10.1103/PhysRevLett.127.227201.

DOI:10.1103/PhysRevLett.127.227201

PMID:34889637

Abstract

Spin-orbit Mott insulators composed of t_{2g}^{4} transition metal ions may host excitonic magnetism due to the condensation of spin-orbital J=1 triplons. Prior experiments suggest that the 4d antiferromagnet Ca_{2}RuO_{4} embodies this notion, but a J=0 nonmagnetic state as a basis of the excitonic picture remains to be confirmed. We use Ru L_{3}-edge resonant inelastic x-ray scattering to reveal archetypal J multiplets with a J=0 ground state in the cubic compound K_{2}RuCl_{6}, which are well described within the LS-coupling scheme. This result highlights the critical role of unquenched orbital moments in 4d-electron compounds and calls for investigations of quantum criticality and excitonic magnetism on various crystal lattices.

摘要

由(t_{2g}^{4})过渡金属离子组成的自旋轨道莫特绝缘体可能由于自旋轨道(J = 1)三重子的凝聚而呈现激子磁性。先前的实验表明，(4d)反铁磁体(Ca_{2}RuO_{4})体现了这一概念，但作为激子图景基础的(J = 0)非磁性态仍有待证实。我们利用钌(L_{3})边共振非弹性X射线散射揭示了立方化合物(K_{2}RuCl_{6})中具有(J = 0)基态的典型(J)多重态，这些多重态在LS耦合方案中得到了很好的描述。这一结果突出了未淬灭轨道矩在(4d)电子化合物中的关键作用，并呼吁对各种晶格上的量子临界性和激子磁性进行研究。