Multistage spin correlations in the S = 1/2 stuffed hyper-star lattice Li2Cu2(MoO4)3
Dr. Raman Sankar and his group, in collaboration with Prof. Kwang-Yong Choi at Sungkyunkwan University (Republic of Korea) investigated The star lattice, which can be visualized as a honeycomb network with each vertex replaced by a triangle, provides a rare platform for realizing exotic quantum states such as quantum spin liquids and disorder-driven random-singlet (RS) states. Herein, we investigate the ground-state properties of the three-dimensional (3D) stuffed hyper-star lattice Li2Cu2(MoO4)3, which exhibits a crossover from short-range spin correlations to a disorder-driven RS-like state below T ∗ ∼ 15.8 K. Thermodynamic and microscopic measurements capture this crossover through a change in the power-law behavior of various observables, from ∼T 0.25 for T > T* to
∼T −0.50 for T < T*. Upon further cooling, a quasifrozen state emerges near Tf = 0.32 K, likely associated with weakly coupled spin chains within the hyper-star spin network. Our results underscore the crucial role of orphan spins and weak residual interactions in stabilizing a disorder-driven quantum-disordered state in three dimensions.
Journal Links: https://journals.aps.org/prb/pdf/10.1103/nv1l-dgv9?