Highly tunable time-reversal-invariant topological superconductivity in topological insulator thin films

Abstract

We study time-reversal-invariant topological superconductivity in topological insulator (TI) thin films including both intra- and inter-surface pairing. We find a nontrivial topology for multiple different configurations. For intra-surface pairing a $\pi$-phase difference between the intra-surface pairing states is required. We show that in this case the resulting topological phase is highly tunable by both an applied electric field and varied chemical potential. For spin-singlet inter-surface pairing, a sign-changing tunnel coupling present in many TI thin films is needed, and again, the topology can be tuned by electric field or doping. Notably, we find that the required inter-surface pairing strength for achieving nontrivial topology can still be subdominant compared to the intra-surface pairing. Finally, for spin-triplet inter-surface pairing we prove that the superconducting state is always topological nontrivial. We show that thin films of Cu-doped Bi${}_2$Se${}_3$ will likely host such spin-triplet inter-surface pairing. Taken together, these results show that time-reversal-invariant topological superconductivity is common in superconducting TI thin films and that the topological phase and its Kramers pair of Majorana edge modes is highly tunable with an applied electric field and varied chemical potential.

10 pages, 6 figures

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Cited by in corpus (18)

• Second Order Topological Superconductivity in $\pi$-Junction Rashba Layers
• Surface Bogoliubov-Dirac cones and helical Majorana hinge modes in superconducting Dirac semimetals
• Dia- and paramagnetic Meissner effect from odd-frequency pairing in multi-orbital superconductors
• Chiral Superconductivity in Thin Films of doped Bi${}_2$Se${}_3$
• Rashba Sandwiches with Topological Superconducting Phases
• Catalogue of Andreev spectra and Josephson effects in structures with time-reversal-invariant topological superconductor wires
• Proximity induced time-reversal topological superconductivity in Bi2Se3 films without phase tuning
• Survival of the fractional Josephson effect in time-reversal-invariant topological superconductors
• Josephson junctions of 2D time-reversal invariant superconductors: signatures of the topological phase
• Time-Reversal Invariant Topological Superconductivity in Planar Josephson Bijunction
• Direct detection of odd-frequency superconductivity via time- and angle-resolved photoelectron fluctuation spectroscopy
• Exact analytical solution of a time-reversal-invariant topological superconducting wire
• RKKY interaction at helical edges of topological superconductors
• Highly tunable magnetic coupling in ultrathin topological insulator films due to impurity resonances
• Diamagnetic Meissner response of odd-frequency superconducting pairing from quantum geometry
• Intrinsic chiral topological superconductor thin films
• Binding zero modes with fluxons in Josephson junctions of time-reversal invariant topological superconductors
• Realizing Majorana Kramers pairs in two-channel InAs-Al nanowires with highly misaligned electric fields