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

Malcolm J.A. Jardine; Derek Dardzinski; Maituo Yu; Amrita Purkayastha; An Hsi Chen; Yu Hao Chang; Aaron Engel; Vladimir N. Strocov; Moïra Hocevar; Chris Palmstro̷m; Sergey M. Frolov; Noa Marom

doi:10.1021/acsami.3c00323

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

Malcolm J.A. Jardine, Derek Dardzinski, Maituo Yu, Amrita Purkayastha, An Hsi Chen, Yu Hao Chang, Aaron Engel, Vladimir N. Strocov, Moïra Hocevar, Chris Palmstro̷m, Sergey M. Frolov, Noa Marom

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

Abstract

Majorana zero modes, with prospective applications in topological quantum computing, are expected to arise in superconductor/semiconductor interfaces, such as β-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 α-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 2020, 6, 180 ]. The results of DFT+U(BO) are validated against angle resolved photoemission spectroscopy (ARPES) experiments for α-Sn and CdTe. For CdTe, the z-unfolding method [ Advanced Quantum Technologies 2022, 5, 2100033 ] 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/α-Sn, InSb/CdTe, and CdTe/α-Sn, as well as in trilayer interfaces of InSb/CdTe/α-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 α-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.

Original language	English
Pages (from-to)	16288-16298
Number of pages	11
Journal	ACS Applied Materials and Interfaces
Volume	15
Issue number	12
DOIs	https://doi.org/10.1021/acsami.3c00323
State	Published - Mar 29 2023
Externally published	Yes

Funding

We thank Guang Bian from the University of Missouri, Li Fu from Northwestern Polytechnical University, China, and Tai C. Chiang from the University of Illinois at Urbana─Champaign for sharing their ARPES data for CdTe. Work at the University of Pittsburgh was supported by the Department of Energy through Grant DE-SC-0019274. Work at CMU and UCSB was funded by the National Science Foundation (NSF) through Grant OISE-1743717. Work in Grenoble is supported by the ANR-NSF PIRE:HYBRID, Transatlantic Research Partnership and IRP-CNRS HYNATOQ. This research used computing resources of the University of Pittsburgh Center for Research Computing, which is supported by NIH Award Number S10OD028483 and of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility, operated under Contract No. DE-AC02-05CH11231.

Keywords

CdTe
InSb
Sn
angle resolved photoemission spectroscopy
density functional theory
electronic structure
metal−semiconductor interface
tunnel barrier

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10.1021/acsami.3c00323

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title = "First-Principles Assessment of CdTe as a Tunnel Barrier at the α-Sn/InSb Interface",

abstract = "Majorana zero modes, with prospective applications in topological quantum computing, are expected to arise in superconductor/semiconductor interfaces, such as β-Sn and InSb. However, proximity to the superconductor may also adversely affect the semiconductor{\textquoteright}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 α-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 2020, 6, 180 ]. The results of DFT+U(BO) are validated against angle resolved photoemission spectroscopy (ARPES) experiments for α-Sn and CdTe. For CdTe, the z-unfolding method [ Advanced Quantum Technologies 2022, 5, 2100033 ] is used to resolve the contributions of different kz 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/α-Sn, InSb/CdTe, and CdTe/α-Sn, as well as in trilayer interfaces of InSb/CdTe/α-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 α-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.",

keywords = "CdTe, InSb, Sn, angle resolved photoemission spectroscopy, density functional theory, electronic structure, metal−semiconductor interface, tunnel barrier",

author = "Jardine, {Malcolm J.A.} and Derek Dardzinski and Maituo Yu and Amrita Purkayastha and Chen, {An Hsi} and Chang, {Yu Hao} and Aaron Engel and Strocov, {Vladimir N.} and Mo{\"i}ra Hocevar and Chris Palmstro̷m and Frolov, {Sergey M.} and Noa Marom",

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year = "2023",

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doi = "10.1021/acsami.3c00323",

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T1 - First-Principles Assessment of CdTe as a Tunnel Barrier at the α-Sn/InSb Interface

AU - Jardine, Malcolm J.A.

AU - Dardzinski, Derek

AU - Yu, Maituo

AU - Purkayastha, Amrita

AU - Chen, An Hsi

AU - Chang, Yu Hao

AU - Engel, Aaron

AU - Strocov, Vladimir N.

AU - Hocevar, Moïra

AU - Palmstro̷m, Chris

AU - Frolov, Sergey M.

AU - Marom, Noa

PY - 2023/3/29

Y1 - 2023/3/29

N2 - Majorana zero modes, with prospective applications in topological quantum computing, are expected to arise in superconductor/semiconductor interfaces, such as β-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 α-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 2020, 6, 180 ]. The results of DFT+U(BO) are validated against angle resolved photoemission spectroscopy (ARPES) experiments for α-Sn and CdTe. For CdTe, the z-unfolding method [ Advanced Quantum Technologies 2022, 5, 2100033 ] is used to resolve the contributions of different kz 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/α-Sn, InSb/CdTe, and CdTe/α-Sn, as well as in trilayer interfaces of InSb/CdTe/α-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 α-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.

AB - Majorana zero modes, with prospective applications in topological quantum computing, are expected to arise in superconductor/semiconductor interfaces, such as β-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 α-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 2020, 6, 180 ]. The results of DFT+U(BO) are validated against angle resolved photoemission spectroscopy (ARPES) experiments for α-Sn and CdTe. For CdTe, the z-unfolding method [ Advanced Quantum Technologies 2022, 5, 2100033 ] is used to resolve the contributions of different kz 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/α-Sn, InSb/CdTe, and CdTe/α-Sn, as well as in trilayer interfaces of InSb/CdTe/α-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 α-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.

KW - CdTe

KW - InSb

KW - Sn

KW - angle resolved photoemission spectroscopy

KW - density functional theory

KW - electronic structure

KW - metal−semiconductor interface

KW - tunnel barrier

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JF - ACS Applied Materials and Interfaces

IS - 12

ER -

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

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