| The low energy quasiparticle dispersions of various narrow gap and gapless semiconductors are respectively described by the three dimensional massive and massless Dirac fermions. The three dimensional Dirac spinor structure allows for a time-reversal invariant, odd parity topological superconducting state. I show that the electrodynamics of this state is described by the Landau-Ginzburg theory augmented by a quantized axion term. I will discuss the bulk-boundary correspondence for this theory, and its implications for the nature of the surface Andreev states and the one dimensional gapless modes along the line vortex. Finally, I will consider the experimental consequences of this effective field theory for the superconducting states in CuxBi2Se3 and Sn1-xInxTe. |
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