paper

First Order Preemptive Ising-nematic Transition in K $_{5}$ Fe $_{4}$ Ag $_{6}$ Te $_{10}$

arXiv:2407.14706

Abstract

Employing inelastic X-ray scattering and neutron scattering techniques, we observed nematic and magnetic phase transitions with distinct characters in K $_{5}$ Fe $_{4}$ Ag $_{6}$ Te $_{10}$ . Upon cooling, the nematic order undergoes a strongly first-order phase transition followed by a second-order magnetic transition at $T_{N}$ $\approx$ 34.6 K. The temperature difference between these two phase transitions is $\sim$ 1 K. The observed phenomenon can be attributed to a distinctive first-order preemptive Ising-nematic transition, a characteristic unique to a quasi-two-dimensional scenario marked by strong out-of-plane spatial anisotropy due to weak coupling. Our studies establish K $_{5}$ Fe $_{4}$ Ag $_{6}$ Te $_{10}$ as the first material in the family of iron pnictides and chalcogenides that possesses a nematic tricritical point preceding the magnetic one upon decreasing nematic coupling.

7 pages, 5 figures

First Order Preemptive Ising-nematic Transition in K5​Fe4​Ag6​Te10​

Abstract

First Order Preemptive Ising-nematic Transition in K $_{5}$ Fe $_{4}$ Ag $_{6}$ Te $_{10}$