Pressure Evolution of Magnetic Structure and Quasiparticle Excitations in Anisotropic Frustrated Zigzag Chains

TL;DR

This study investigates how hydrostatic pressure influences magnetic structures and quasiparticle excitations in the frustrated zigzag chain compound YbCuS2, revealing pressure-induced magnetic and quasiparticle state changes.

Contribution

It provides new insights into pressure effects on magnetic order and quasiparticles in anisotropic frustrated chains, highlighting the role of pressure in tuning quantum states.

Findings

Pressure increases the magnetic transition temperature TN.

Magnetic structure shifts from incommensurate to commensurate order under pressure.

Pressure suppresses gapless quasiparticle excitations.

Abstract

Frustrated magnetic systems with anisotropic exchange interactions have been recognized as key platforms for discovering exotic quantum states and quasiparticles. In this study, we report the pressure evolution of magnetic structures and quasiparticle excitations in the frustrated semiconductor YbCuS2, characterized by Yb3+ zigzag chains with competing exchange interactions. At ambient pressure, YbCuS2 exhibits a magnetic transition at TN ~ 0.95 K, forming an incommensurate helical magnetic order. Under hydrostatic pressure of 1.6 GPa, TN increases to 1.17 K, and the magnetic structure changes to a commensurate one, which can be regarded as an odd-parity magnetic multipole order. Remarkably, pressure suppresses the gapless quasiparticle excitations. These findings suggest that pressure alters the exchange interactions between the Yb ions, affecting both the magnetic ground state and the quasiparticle excitations. Our results highlight the pivotal role of anisotropic interactions in one-dimensionality to stabilize the complex quantum phases, offering insights into the interplay among frustration, dimensionality, multipoles and emergent quasiparticles.