Emerging Majorana Zero Modes in Topologically Trivial Dirac Nodal Loop Semimetal Superconductors with Even Parity

We reveal that the topologically nontrivial Dirac nodal loop semimetal will become topologically trivial in the superconducting state with the even parity. Interestingly, the Majorana zero modes can still be realized in this topologically trivial state. In the presence of a vortex line, a pair of Majorana zero modes emerge in the vortex core. The appearance/disappearance of the Majorana zero modes can be characterized by the Z(2) topological invariant. Moreover, a vortex phase transition occurs upon changing the chemical potential.

Automated summary

This study reveals that the topologically nontrivial Dirac nodal loop semimetal becomes topologically trivial in the superconducting state with even parity. However, interestingly, the realization of Majorana zero modes is still possible in this topologically trivial state. In the presence of a vortex line, a pair of Majorana zero modes emerge in the vortex core. The occurrence/disappearance of Majorana zero modes can be characterized by the Z(2) topological invariant. Moreover, a vortex phase transition occurs upon changing the chemical potential.