Strain Tuning Three-state Potts Nematicity in a Correlated Antiferromagnet

TL;DR

This study demonstrates reversible strain control of three-state Potts nematicity in a zigzag antiferromagnetic insulator, revealing tunable phase transitions and nematic susceptibility near magnetic ordering.

Contribution

It introduces a method to reversibly manipulate three-state Potts nematicity in a C3 symmetric material using strain, enabling detailed exploration of nematic phase transitions.

Findings

Reversible strain can rotate the nematic director by 2π/3 or π/2.

The nematic phase transition can be tuned from crossover to Potts or Ising flop transitions.

Nematic susceptibility diverges near the magnetic ordering temperature.

Abstract

Electronic nematicity, a state in which rotational symmetry is spontaneously broken, has become a familiar characteristic of many strongly correlated materials. One widely studied example is the discovered Ising-nematicity and its interplay with superconductivity in tetragonal iron pnictides. Since nematic directors in crystalline solids are restricted by the underlying crystal symmetry, recently identified quantum material systems with three-fold rotational (C$_3$) symmetry offer a new platform to investigate nematic order with three-state Potts character. Here, we report reversible strain control of the three-state Potts nematicity in a zigzag antiferromagnetic insulator, FePSe$_3$. Probing the nematicity via optical linear dichroism, we demonstrate either $2{\pi}/3$ or ${\pi}/2$ rotation of nematic director by uniaxial strain. The nature of the nematic phase transition can also be controlled such that it undergoes a smooth crossover transition, a Potts nematic transition, or a Ising nematic flop transition. Further elastocaloric measurements demonstrate signatures of two coupled phase transitions, indicating that the nematic phase is a vestigial order arose from the antiferromagnetism. The ability to tune the nematic order with in-situ strain further enables the extraction of nematic susceptibility, which exhibits a divergent behavior near the magnetic ordering temperature that is corroborated with both linear dichroism and elastocaloric measurements. Our work points to an active control approach to manipulate and explore nematicity in three-state Potts correlated materials.