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arXiv · 0901.1343

Lattice model of three-dimensional topological singlet superconductor with time-reversal symmetry

Andreas P. Schnyder·Shinsei Ryu·Andreas W. W. Ludwig
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Abstract

We study topological phases of time-reversal invariant singlet superconductors in three spatial dimensions. In these particle-hole symmetric systems the topological phases are characterized by an even-numbered winding number $ν$. At a two-dimensional (2D) surface the topological properties of this quantum state manifest themselves through the presence of $ν$ flavors of gapless Dirac fermion surface states, which are robust against localization from random impurities. We construct a tight-binding model on the diamond lattice that realizes a topologically nontrivial phase, in which the winding number takes the value $ν=\pm 2$. Disorder corresponds to a (non-localizing) random SU(2) gauge potential for the surface Dirac fermions, leading to a power-law density of states $ρ(ε) \sim ε^{1/7}$. The bulk effective field theory is proposed to be the (3+1) dimensional SU(2) Yang-Mills theory with a theta-term at $θ=π$.

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Andreas P. Schnyder, Shinsei Ryu, Andreas W. W. Ludwig. 2009-01-10. Lattice model of three-dimensional topological singlet superconductor with time-reversal symmetry. https://doi.org/10.1103/physrevlett.102.196804

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