Tunable quantum spin liquidity in the 1/6th-filled breathing kagome lattice

TL;DR

This study demonstrates how chemical pressure tuning in Li$_2$In$_{1-x}$Sc$_x$Mo$_3$O$_8$ induces a transition from antiferromagnetic order to a quantum spin liquid in a breathing kagome lattice, highlighting the role of lattice symmetry.

Contribution

It reveals the control of quantum spin liquid phases through the breathing parameter in a 1/6-filled kagome lattice, linking lattice symmetry and magnetic frustration.

Findings

Chemical pressure tunes magnetic phases from order to spin liquid.

Breathing parameter correlates with the emergence of quantum spin liquid.

Specific heat data supports the presence of a $U(1)$ quantum spin liquid.

Abstract

We present measurements on a series of materials, Li$_2$In$_{1-x}$Sc$_x$Mo$_3$O$_8$, that can be described as a 1/6th-filled breathing kagome lattice. Substituting Sc for In generates chemical pressure which alters the breathing parameter non-monotonically. $\mu$SR experiments show that this chemical pressure tunes the system from antiferromagnetic long range order to a quantum spin liquid phase. A strong correlation with the breathing parameter implies that it is the dominant parameter controlling the level of magnetic frustration, with increased kagome symmetry generating the quantum spin liquid phase. Magnetic susceptibility measurements suggest that this is related to distinct types of charge order induced by changes in lattice symmetry, in line with the theory of Chen et al. [Phys. Rev. B 93, 245134 (2016)]. The specific heat for samples at intermediate Sc concentration and with minimal breathing parameter, show consistency with the predicted $U(1)$ quantum spin liquid.