Multi-Band Superconductivity in Strongly Hybridized 1T'-WTe${}_2$/NbSe${}_2$ Heterostructures

Abstract

The interplay of topology and superconductivity has become a subject of intense research in condensed matter physics for the pursuit of topologically non-trivial forms of superconducting pairing. An intrinsically normal-conducting material can inherit superconductivity via electrical contact to a parent superconductor via the proximity effect, usually understood as Andreev reflection at the interface between the distinct electronic structures of two separate conductors. However, at high interface transparency, strong coupling inevitably leads to changes in the band structure, locally, owing to hybridization of electronic states. Here, we investigate such strongly proximity-coupled heterostructures of monolayer 1T'-WTe${}_2$, grown on NbSe${}_2$ by van-der-Waals epitaxy. The superconducting local density of states (LDOS), resolved in scanning tunneling spectroscopy down to 500~mK, reflects a hybrid electronic structure, well-described by a multi-band framework based on the McMillan equations which captures the multi-band superconductivity inherent to the NbSe${}_2$ substrate and that induced by proximity in WTe${}_2$, self-consistently. Our material-specific tight-binding model captures the hybridized heterostructure quantitatively, and confirms that strong inter-layer hopping gives rise to a semi-metallic density of states in the 2D WTe${}_2$ bulk, even for nominally band-insulating crystals. The model further accurately predicts the measured order parameter $\Delta \simeq 0.6$~meV induced in the WTe${}_2$ monolayer bulk, stable beyond a 2~T magnetic field. We believe that our detailed multi-band analysis of the hybrid electronic structure provides a useful tool for sensitive spatial mapping of induced order parameters in proximitized atomically thin topological materials.

References in corpus (45)

• Quantum Spin Hall Effect in Graphene
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• New directions in the pursuit of Majorana fermions in solid state systems
• Type-II Weyl Semimetals
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Search for Majorana fermions in superconductors
• Bismuthene on a SiC Substrate: A Candidate for a New High-Temperature Quantum Spin Hall Paradigm
• Josephson Current and Noise at a Superconductor-Quantum Spin Hall Insulator-Superconductor Junction
• Realization of Quantum Spin Hall State in Monolayer 1T'-WTe2
• Observation of the Quantum Spin Hall Effect up to 100 Kelvin in a Monolayer Crystal
• Edge conduction in monolayer WTe2
• Observation of Majorana fermions with spin selective Andreev reflection in the vortex of topological superconductor
• Probing Neutral Majorana Fermion Edge Modes with Charge Transport
• Electrically Tunable Low Density Superconductivity in a Monolayer Topological Insulator
• Gate-induced superconductivity in a monolayer topological insulator
• Higher-Order Topology, Monopole Nodal Lines, and the Origin of Large Fermi Arcs in Transition Metal Dichalcogenides XTe${}_2$ (X=Mo,W)
• Electric Field-Tuned Topological Phase Transition in Ultra-Thin Na3Bi - Towards a Topological Transistor
• Two energy gaps and Fermi surface 'arcs' in NbSe2
• Imaging Quantum Spin Hall Edges in Monolayer WTe2
• Atomic-Scale Interface Engineering of Majorana Edge Modes in a 2D Magnet-Superconductor Hybrid System
• Observation of a Majorana zero mode in a topologically protected edge channel
• On the quantum spin Hall gap of monolayer 1T'-WTe2
• Direct Visualization of 2D Topological Insulator in Single-layer 1T'-WTe2
• Time-Reversal-Invariant $Z_4$ Fractional Josephson Effect
• Penetration depth study of superconducting gap structure of 2\textit{H}-NbSe${}_2$
• Evidence of Higher Order Topology in Multilayer WTe${}_2$ from Josephson Coupling through Anisotropic Hinge States
• Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe${}_2$
• Unusual suppression of the superconducting energy gap and critical temperature in atomically thin NbSe2
• Using controlled disorder to probe the interplay between charge order and superconductivity in NbSe2
• Spectroscopy of bulk and few-layer superconducting NbSe${}_2$ with van der Waals tunnel junctions
• Tomonaga-Luttinger liquid in the edge channels of a quantum spin Hall insulator
• Inversion-protected higher order topological superconductivity in monolayer WTe${}_2$
• Understanding topological phase transition in transition metal dichalcogenides
• Strain Tunable Semimetal-Topological-Insulator Transition in Monolayer 1T'-WTe2
• Non-Abelian parafermions in time-reversal invariant interacting helical systems
• One-Dimensional Edge Transport in Few-Layer WTe${}_2$
• Landau Quantization and Highly Mobile Fermions in an Insulator
• Atomic-Scale Strain Manipulation of a Charge Density Wave
• Atomically Thin Quantum Spin Hall Insulators
• Proximity-Induced Superconductivity with Subgap Anomaly in Type II Weyl Semi-Metal WTe2
• Robust linear magnetoresistance in WTe2
• The influence of lattice termination on the edge states of the quantum spin Hall insulator monolayer $1T^{\prime }$-WTe${}_2$
• Tunneling into the vortex state of NbSe${}_2$ with van der Waals junctions

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• Role of interface hybridization on induced superconductivity in 1T${}^{\prime }$-WTe${}_2$ and 2H-NbSe${}_2$ heterostructures
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