The topological properties of D+p-wave superconductors in the mixed Rashba/Dresselhaus systems

We investigate the effect of mixing Rashba/Dresselhaus spin-orbit couplings (SOCs) on the topological properties of D + p-wave superconductors. It is known that the nodal D + p-wave Rashba superconductors become gapful under a Zeeman magnetic field. We extend this gap-generation mechanism to mixed Rashba/Dresselhaus systems and find that the induced energy gaps are strongly modified by the Dresselhaus component in the second quadrant of the Brillion zone (BZ). We further calculate the Chern number numerically and obtain the topological phase diagram. It is shown that the Dresselhaus SOCs have a negative effect on the topological properties; the topological nontrivial region withC= -4 in the phase diagram shrinks as the amplitude of the Dresselhaus component increases. In the Dresselhaus-dominated regime, the contributions of gapped nodes from different quadrants of the BZ cancel each other, resulting in zero Chern number in most of the phase diagram. The numerical results are well explained by an approximate analytical formula for Chern number.