Temperature-tuned Fermi-surface topology and segmentation in noncentrosymmetric superconductors

We report the first comprehensive microscopic description of the effect of strong correlations and thermal fluctuations on the properties of noncentrosymmetric superconductors in presence of an in-plane Zeeman field. Away from the weak coupling regime the Bardeen-Cooper-Schrieffer theory breaks down and the supercon-ducting transitions are dictated by the pairing field phase fluctuations. Using a nonperturbative numerical technique viz. static path approximation, we demonstrate that short-range fluctuating superconducting pair correlations give rise to Fermi-surface segmentation with direction-dependent pair breaking and hot spots for quasiparticle scattering. A fluctuation-driven finite-temperature topological transition of the Fermi surface is realized, characterized by a shift of the corresponding Dirac point from k = 0 to k not equal 0. Our results provide key benchmarks for the thermal scales and regimes of thermal stability of the properties of these systems, which are important for device applications. Our numerical estimates are in fairly good qualitative agreement with the recent differential conductance and quasiparticle interference measurements on Bi2Te3/NbSe2 hybrid. A generic theoretical framework for the finite momentum scattering of quasiparticles and the associated spectroscopic features is proposed, which is expected to be applicable to a wide class of superconducting materials.