Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 99: Superconductivity: (General) Theory 2
TT 99.6: Vortrag
Donnerstag, 19. März 2015, 16:15–16:30, H 2053
Surface instability of nodal noncentrosymmetric superconductors — •Carsten Timm1, Stefan Rex2, and Philip M. R. Brydon3 — 1Institute of Theoretical Physics, Technische Universität Dresden, Germany — 2Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway — 3Condensed Matter Theory Center, The University of Maryland, College Park, U.S.A.
It has been proposed that nodal noncentrosymmetric superconductors show flat bands of zero-energy surface states [1,2]. Such surface states would realize a two-dimensional gas of Majorana fermions with interesting properties. However, the proposal was based on the assumption that the superconducting gaps assume constant bulk values even in the presence of a surface. We here employ self-consistent mean-field theory to calculate the gaps and the surface states for a slab of finite thickness. We find two phase transitions upon lowering the temperature: At a higher temperature Tc, the slab becomes superconducting and develops flat surface bands. At a lower temperature Ts, time-reversal invariance is spontaneously broken in the surface region and the surface bands become dispersive and are pushed away from the Fermi energy.
[1] A. P. Schnyder and S. Ryu, Phys. Rev. B 84, 060504(R) (2011).
[2] P. M. R. Brydon, A. P. Schnyder, and C. Timm,
Phys. Rev. B 84, 020501(R) (2011).