Robustness of Majorana Modes and Minigaps in a Spin-Orbit-Coupled Semiconductor-Superconductor Heterostructure

Abstract

We study the robustness of Majorana zero energy modes and minigaps of quasiparticle excitations in a vortex by numerically solving Bogoliubov-deGennes equations in a heterostructure composed of an \textit{s} -wave superconductor, a spin-orbit-coupled semiconductor thin film, and a magnetic insulator. This heterostructure was proposed recently as a platform for observing non-Abelian statistics and performing topological quantum computation. The dependence of the Majorana zero energy states and the minigaps on various physics parameters (Zeeman field, chemical potential, spin-orbit coupling strength) is characterized. We find the minigaps depend strongly on the spin-orbit coupling strength. In certain parameter region, the minigaps are linearly proportional to the \textit{s}-wave superconducting pairing gap ${\Delta }_s$, which is very different from the ${\Delta }_s^2$ dependence in a regular \textit{s-} or \textit{\p}-wave superconductor. We characterize the zero energy chiral edge state at the boundary and calculate the STM signal in the vortex core that shows a pronounced zero energy peak. We show that the Majorana zero energy states are robust in the presence of various types of impurities. We find the existence of impurity potential may increase the minigaps and thus benefit topological quantum computation.

11 pages, 15 figures

References in corpus (16)

• Non-Abelian Anyons and Topological Quantum Computation
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures
• Non-Abelian Topological Order in S-Wave Superfluids of Ultracold Fermionic Atoms
• Electrically detected interferometry of Majorana fermions in a topological insulator
• $p_x+i{p}_y$ superfluid from s-wave interactions of fermionic cold atoms
• Detecting Non-Abelian Statistics in the nu=5/2 Fractional Quantum Hall State
• Quantum Computation Using Vortices and Majorana Zero Modes of a $p_x$ + $i{p}_y$ Superfluid of Fermionic Cold Atoms
• Proximity effect at the superconductor - topological insulator interface
• Splitting of Majorana modes due to intervortex tunneling in a p + ip superconductor
• Anisotropic Fermi Superfluid via p-wave Feshbach Resonance
• Zero modes of two-dimensional chiral p-wave superconductors
• An Index Theorem for the Majorana Zero Modes in Chiral P-Wave Superconductors
• Testable signatures of quantum non-locality in a two-dimensional chiral p-wave superconductor
• Anyonic Braiding in Optical Lattices
• Bulk-edge coupling in the non-abelian $\nu =5/2$ quantum Hall interferometer

Cited by in corpus (1)

• Surface density of states and topological edge states in non-centrosymmetric superconductors