Lattice-Shifted Nematic Quantum Critical Point in FeSe${}_{1-x}$S${}_x$

Abstract

We report the evolution of nematic fluctuations in FeSe${}_{1-x}$S${}_x$ single crystals as a function of Sulfur content $x$ across the nematic quantum critical point (QCP) $x_c\sim$ 0.17 via Raman scattering. The Raman spectra in the $B_{1g}$ nematic channel consist of two components, but only the low energy one displays clear fingerprints of critical behavior and is attributed to itinerant carriers. Curie-Weiss analysis of the associated nematic susceptibility indicates a substantial effect of nemato-elastic coupling which shifts the location of the nematic QCP. We argue that this lattice-induced shift likely explains the absence of any enhancement of the superconducting transition temperature at the QCP. The presence of two components in the nematic fluctuations spectrum is attributed to the dual aspect of electronic degrees of freedom in Hund's metals, with both itinerant carriers and local moments contributing to the nematic susceptibility.

10 pages, 5 figures

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Cited by in corpus (10)

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• Elastoresistivity in the incommensurate charge density wave phase of BaNi${}_{\text{2}}$(As${}_{\text{1-x}}$P${}_{\text{x}}$)${}_{\text{2}}$
• Superconductivity Mediated by Nematic Fluctuations in Tetragonal $\text{Fe}{\text{Se}}_{1-x}{\text{S}}_x$
• Electronic Stripe Patterns Near the Fermi Level of Tetragonal Fe(Se,S)
• Evolution of lattice, spin, and charge properties across the phase diagram of FeSe${}_{1-x}$S${}_x$
• Defect-induced electronic smectic state at the surface of nematic materials
• Superconductivity near a nematoelastic quantum critical point
• Nematic fluctuations mediated superconductivity revealed by anisotropic strain in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Superconductivity near an Ising nematic quantum critical point in two dimensions
• Fragile pressure-induced magnetism in FeSe superconductors with a thickness reduction