Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 59: Superconductivity: Fe-based Superconductors - FeSe and others

TT 59.10: Vortrag

Donnerstag, 23. März 2017, 12:00–12:15, HSZ 103

Lattice-assisted nematic order in Ca₁₀Pt₃As₈(Fe_1−xPt_xAs)₁₀ — •Felix Brückner, Vadim Grinenko, Rajib Sarkar, Maksym Surmach, Dmytro Inosov, and Hans-Henning Klauss — Institut für Festkörperphysik, Technische Universität Dresden, Dresden, Germany

A broken 4-fold rotational symmetry, caused by electronic correlation effects, known as nematicity, is a well established fact in many iron-based superconductors. Slanted stacking of crystallographic layers can influence the formation of nematic order. This is investigated at the example of the triclinic system Ca₁₀Pt₃As₈(Fe_1−xPt_xAs)₁₀. We present a joint study including magnetostriction, anisotropic resistivity, NMR and inelastic neutron scattering.

A phase transition at T^* ≈ 40 K, far above the superconducting T_c = 13 K, manifests itself in a change in magnetic dynamic properties and a weak nematic lattice transition as well. NMR studies show a drastic decrease of low-energy magnetic fluctuations and a slight static broadening, interpreted as the opening of a pseudo spin-gap. A peak in the INS spectrum at the antiferromagnetic peak is found below the transition temperature. Since the nematic transition is twinned, we can observe the inequivalence of (1,1,0) and (1,-1,0) directions by applying magnetic field that detwins the sample and by measuring magnetostriction and resistivity. Beside the phase transition at T^* we found a second magnetic phase transition at ≈ 4 K.