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It has recently been pointed out that nodal noncentrosymmetric superconductors have non-trivial topology [1]. In these systems a bulk-boundary correspondence can be developed, which guarantees the existence of a flat band of singly degenerate zero-energy states within regions of the surface Brillouin zone bounded by the projected nodal lines. Using a quasiclassical method we construct the surface spectra, obtain an existence condition for the zero-energy flat bands, and show that they leave distinct signatures in the tunneling conductance [2]. We also find that the zero-energy flat bands are strongly spin-polarized. At interfaces with a ferromagnet, the coupling to the exchange field therefore shifts the energy of these states, hence generating a strong transverse current [3].
[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); A. P. Schnyder, P. M. R. Brydon, and C. Timm, Phys. Rev B 85, 024522 (2012). [3] P. M. R. Brydon, C. Timm, and A. P. Schnyder, in preparation. |
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