Lifting the degeneracy of quantum spin liquid phase by uniaxial pressure

Abstract

We report muon spin relaxation/rotation ($\mu$SR) measurements of the candidate three-dimensional (3D) quantum spin liquid (QSL) PbCuTe${}_2$O${}_6$, hosting $S=1/2$ moments, under controlled in situ [110] uniaxial compression up to ${\sigma }_{[110]}=37.7$~MPa. A small directional lattice perturbation significantly modifies the local magnetic response, while above ${\sigma }_{\mathrm{cr}}\sim 10.8$\,MPa the relaxation rates are strongly enhanced and the internal-field distribution is substantially broadened. These changes occur along with the local crystalline symmetry breaking. While, no evidence for conventional static long-range magnetic order is observed, the compression drives the system towards a structurally modified and strongly correlated state in which enhanced quasi-static correlations coexist with persistent slow spin dynamics. This work demonstrates a clean and symmetry-selective route to control frustrated exchange landscape and access hidden magnetic instabilities in a 3D QSL candidate opening up the possibilities to tune other correlated systems where intrinsic coupling between magnetic and lattice degrees of freedom are relevant.

7 pages, 4 figures. The supplementary information has not been uploaded in the current version