The relationship between transport anisotropy and nematicity in FeSe

Abstract

The mechanism behind the nematicity of FeSe is not known. Through elastoresitivity measurements it has been shown to be an electronic instability. However, so far measurements have extended only to small strains, where the response is linear. Here, we apply large elastic strains to FeSe, and perform two types of measurements. (1) Using applied strain to control twinning, the nematic resistive anisotropy at temperatures below the nematic transition temperature Ts is determined. (2) Resistive anisotropy is measured as nematicity is induced through applied strain at fixed temperature above Ts. In both cases, as nematicity strengthens the resistive anisotropy peaks about about 7%, then decreases. Below ~40 K, the nematic resistive anisotropy changes sign. We discuss possible implications of this behaviour for theories of nematicity. We report in addition: (1) Under experimentally accessible conditions with bulk crystals, stress, rather than strain, is the conjugate field to the nematicity of FeSe. (2) At low temperatures the twin boundary resistance is ~10% of the sample resistance, and must be properly subtracted to extract intrinsic resistivities. (3) Biaxial inplane compression increases both in-plane resistivity and the superconducting critical temperature Tc, consistent with a strong role of the yz orbital in the electronic correlations.

18 pages, 13 figures. To be published in Phys. Rev. X

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Cited by in corpus (12)

• Strain-tuning of nematicity and superconductivity in single crystals of FeSe
• Elastoresistivity in the incommensurate charge density wave phase of BaNi${}_{\text{2}}$(As${}_{\text{1-x}}$P${}_{\text{x}}$)${}_{\text{2}}$
• FeSe and the missing electron pocket problem
• Continuously tunable uniaxial strain control of van der Waals heterostructure devices
• Nematic state of the FeSe superconductor
• Microstructuring YbRh2Si2 for resistance and noise measurements down to ultra-low temperatures
• Resurgence of superconductivity and the role of $d_{xy}$ hole band in FeSe${}_{1-x}$Te${}_x$
• A Ginzburg-Landau approach to the vortex-domain wall interaction in superconductors with nematic order
• Suppression of nematicity by tensile strain in multilayer FeSe/SrTiO${}_3$ films
• Elasto-Raman scattering: arsenic optical phonon as a probe of nematicity in BaFe${}_2$As${}_2$
• Edwards-Anderson parameter and local Ising-nematicity in FeSe revealed via NMR spectral broadening
• Vortices in a Ginzburg Landau Theory of Superconductors with Nematic Order