Multimodal synchrotron x-ray diffraction across the superconducting transition of Sr0.1Bi2Se3

Abstract

In the doped topological insulator SrxBi2Se3, a pronounced in-plane twofold symmetry is observed in electronic properties below the superconducting transition temperature Tc∼3K, despite the threefold symmetry of the observed R3¯m space group. The axis of twofold symmetry is nominally pinned to one of three rotationally equivalent crystallographic directions and crystallographic strain has been proposed to be the origin of this pinning. We carried out multimodal synchrotron diffraction and resistivity measurements down to ∼0.68K and in magnetic fields up to 45 kG on a single crystal of SrxBi2Se3 to probe the effect of superconductivity on the crystallographic distortion. Our results indicate that there is no in-plane crystallographic distortion at the level of 1×10−5 associated with the superconducting transition. These results further support the model that the large twofold in-plane anisotropy of superconducting properties of SrxBi2Se3 is not structural in origin, but electronic, namely, it is caused by a nematic superconducting order parameter of Eu symmetry.

Source-reported materials — not catalogue approval

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