First Principles Assessment of CdTe as a Tunnel Barrier at the $\alpha$-Sn/InSb Interface

Abstract

Majorana zero modes, with prospective applications in topological quantum computing, are expected to arise in superconductor/semiconductor interfaces, such as $\beta$-Sn and InSb. However, proximity to the superconductor may also adversely affect the semiconductor's local properties. A tunnel barrier inserted at the interface could resolve this issue. We assess the wide band gap semiconductor, CdTe, as a candidate material to mediate the coupling at the lattice-matched interface between $\alpha$-Sn and InSb. To this end, we use density functional theory (DFT) with Hubbard U corrections, whose values are machine-learned via Bayesian optimization (BO) [npj Computational Materials 6, 180 (2020)]. The results of DFT+U(BO) are validated against angle resolved photoemission spectroscopy (ARPES) experiments for $\alpha$-Sn and CdTe. For CdTe, the z-unfolding method [Advanced Quantum Technologies, 5, 2100033 (2022)] is used to resolve the contributions of different $k_z$ values to the ARPES. We then study the band offsets and the penetration depth of metal-induced gap states (MIGS) in bilayer interfaces of InSb/$\alpha$-Sn, InSb/CdTe, and CdTe/$\alpha$-Sn, as well as in tri-layer interfaces of InSb/CdTe/$\alpha$-Sn with increasing thickness of CdTe. We find that 16 atomic layers (3.5 nm) of CdTe can serve as a tunnel barrier, effectively shielding the InSb from MIGS from the $\alpha$-Sn. This may guide the choice of dimensions of the CdTe barrier to mediate the coupling in semiconductor-superconductor devices in future Majorana zero modes experiments.

References in corpus (40)

• Non-Abelian Anyons and Topological Quantum Computation
• Topological Insulators with Inversion Symmetry
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures
• Helical liquids and Majorana bound states in quantum wires
• Majorana Zero Modes and Topological Quantum Computation
• Predicting Band Gaps with Hybrid Density Functionals
• Milestones toward Majorana-based quantum computing
• Epitaxy of Semiconductor-Superconductor nanowires
• Near-zero-energy end states in topologically trivial spin-orbit coupled superconducting nanowires with a smooth confinement
• Majorana qubit decoherence by quasiparticle poisoning
• Non-Majorana states yield nearly quantized conductance in superconductor-semiconductor nanowire devices
• Elemental Topological Insulator with a Tunable Fermi Level: Strained α-Sn on InSb(001)
• Effects of gate-induced electric fields on semiconductor Majorana nanowires
• Elemental topological Dirac semimetal: α-Sn on InSb(111)
• Angle-resolved photoemission spectroscopy
• Dirac cone with helical spin polarization in ultrathin $\alpha$-Sn(001) films
• Gapped Electronic Structure of Epitaxial Stanene on InSb(111)
• Metallization of Rashba wire by superconducting layer in the strong-proximity regime
• Effective theory approach to the Schrodinger-Poisson problem in semiconductor Majorana devices
• Epitaxial Pb on InAs nanowires
• Zero-energy pinning of topologically-trivial bound states in multi-band semiconductor-superconductor nanowires
• Shadow epitaxy for in-situ growth of generic semiconductor/superconductor devices
• Effects of large induced superconducting gap on semiconductor Majorana nanowires
• Tensile Strained Gray Tin: a New Dirac Semimetal for Observing Negative Magnetoresistance with Shubnikov-de-Haas Oscillation
• Finite-size effects in a nanowire strongly coupled to a thin superconducting shell
• Three-dimensional band structure of layered TiTe2: Photoemission final-state effects
• Ab initio theory of plasmonic superconductivity within the Eliashberg and density-functional formalisms
• The topological surface state of $\alpha$-Sn on InSb(001) as studied by photoemission
• Majorana Braiding in Realistic Nanowire Y-Junctions and Tuning Forks
• Subband occupation in semiconductor-superconductor nanowires
• Double Band Inversion in $\alpha$-Sn: Appearance of Topological Surface States and the Role of Orbital Composition
• Growth and Magnetotransport in Thin Film α-Sn on CdTe
• Tailoring the topological surface state in ultrathin $\alpha$-Sn (111) films
• Thermal Stability Enhancement in Epitaxial α-Sn Films by Strain Engineering
• First principles feasibility assessment of a topological insulator at the InAs/GaSb interface
• Structural and electronic properties of the pure and stable elemental 3D topological Dirac semimetal $\alpha$-Sn
• Band Mapping in One-Step Photoemission Theory: Multi-Bloch-Wave Structure of Final States and Interference Effects
• Dependence of the electronic structure of the EuS/InAs interface on the bonding configuration
• Integrating micromagnets and hybrid nanowires for topological quantum computing

Cited by in corpus (2)

• Structure Prediction of Ionic Epitaxial Interfaces with Ogre Demonstrated for Colloidal Heterostructures of Lead Halide Perovskites
• 3D Topological Semimetal Phases of Strained $\alpha$-Sn on Insulating Substrate