Johannes Hofmann, University of Würzburg and MPI-Stuttgart
Motivated by recent point contact Andreev reflection measurements on BiPd [1], we study the appearance of topologically protected surface states in non-centrosymmetric superconductors. We determine the signatures of these surface states in quasiparticle interference experiments and show that Fourier transform scanning tunneling spectroscopy (FT-STS) can give direct information about the momentum-space structure of these surface states. In particular, we find that FT-STS allows to distinguish among different types of topological surface states, such as zero-energy flat bands, arc surface states, and helical Majorana modes [2,3]. We investigate non-centrosymmetric superconductors with different point-group symmetries and consider both non-magnetic and magnetic impurity scatterers. In the case of non-magnetic s-wave scatterers, a simple interperation of the quasiparticle interference pattern in terms of the joint density of states is derived.
[1] Mintu Mondal et al., Phys. Rev. B 86, 094520 (2012).
[2] A. P. Schnyder and S. Ryu, Phys. Rev. B 84, 060504(R) (2011).
[3] P. M. R. Brydon, A. P. Schnyder, and C. Timm, Phys. Rev. B 84, 020501(R) (2011); A. P. Schnyder, P. M. R. Brydon, and C. Timm, Phys. Rev. B 85, 024522 (2012).