Visualization of Topological Boundary Modes Manifesting Topological Nodal-Point Superconductivity
arXiv:2112.10240 · doi:10.1038/s41567-021-01376-z
Abstract
The extension of the topological classification of band insulators to topological semimetals gave way to the topology classes of Dirac, Weyl, and nodal line semimetals with their unique Fermi arc and drum head boundary modes. Similarly, there are several suggestions to employ the classification of topological superconductors for topological nodal superconductors with Majorana boundary modes. Here, we show that the surface 1H termination of the transition metal dichalcogenide compound 4Hb-TaS, in which 1T-TaS and 1H-TaS layers are interleaved, has the phenomenology of a topological nodal point superconductor. We find in scanning tunneling spectroscopy a residual density of states within the superconducting gap. An exponentially decaying bound mode is imaged within the superconducting gap along the boundaries of the exposed 1H layer characteristic of a gapless Majorana edge mode. The anisotropic nature of the localization length of the edge mode aims towards topological nodal superconductivity. A zero-bias conductance peak is further imaged within fairly isotropic vortex cores. All our observations are accommodated by a theoretical model of a two-dimensional nodal Weyl-like superconducting state, which ensues from inter-orbital Cooper pairing. The observation of an intrinsic topological nodal superconductivity in a layered material will pave the way for further studies of Majorana edge modes and its applications in quantum information processing.
initial submission
References in corpus (11)
- Non-Abelian Anyons and Topological Quantum Computation
- Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
- Evidence of Majorana fermions in an Al - InAs nanowire topological superconductor
- Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
- Observation of a Robust Zero-energy Bound State in Iron-based Superconductor Fe(Te,Se)
- Topological surface states in nodal superconductors
- Possible Topological Superconducting Phases of MoS
- Observation of a Majorana zero mode in a topologically protected edge channel
- Theory of Multi-Orbital Topological Superconductivity in Transition Metal Dichalcogenides
- Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands
- Multiple odd-parity superconducting phases in bilayer transition metal dichalcogenides