Nematic pinning of the superconducting state in the doped topological insulator Sr_xBi₂Se₃

Abstract The discovery of a rotational symmetry breaking, or nematic, state in the superconducting doped topological insulator M x Bi 2 Se 3 (M = Cu, Sr, Nb) indicates multicomponent order parameter which is topological. Many questions remain this family materials. In particular, nematic axis twofold always pinned along one three rotationally equivalent directions threefold symmetric basal plane rhombohedral crystal. Crystallographic strain has been proposed as origin choice pinning axis. Here, we discuss state, summarizing our magnetotransport, magnetization, penetration depth, and calorimetry measurements, support theoretical picture superconductivity. We impact controlled disorder via proton irradiation on results multimodal technique for searching crystallographic below 1 K simultaneous diffraction magnetotransport measurements.