Formation of a Stable Surface Oxide in MnBi2Te4Thin Films

Golrokh Akhgar; Qile Li; Iolanda Di Bernardo; Chi Xuan Trang; Chang Liu; Ali Zavabeti; Julie Karel; Anton Tadich; Michael S. Fuhrer; Mark T. Edmonds

doi:10.1021/acsami.1c19089

Formation of a Stable Surface Oxide in MnBi₂Te₄Thin Films

Golrokh Akhgar, Qile Li, Iolanda Di Bernardo, Chi Xuan Trang, Chang Liu, Ali Zavabeti, Julie Karel, Anton Tadich, Michael S. Fuhrer, Mark T. Edmonds

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

1 Citation (Scopus)

Abstract

Understanding the air stability of MnBi2Te4 thin films is crucial for the development and long-term operation of electronic devices based on magnetic topological insulators. In the present work, we study MnBi2Te4 thin films upon exposure to the atmosphere using a combination of synchrotron-based photoelectron spectroscopy, room-temperature electrical transport, and atomic force microscopy to determine the oxidation process. After 2 days of air exposure, a 2 nm thick oxide passivates the surface, corresponding to the oxidation of only the top two surface layers, with the underlying layers preserved. This protective oxide layer results in samples that still exhibit metallic conduction even after several days of air exposure. Furthermore, the work function decreases from 4.4 eV for pristine MnBi2Te4 to 4.0 eV after the formation of the oxide, along with only a small shift in the core levels, indicating minimal doping as a result of air exposure. With the oxide confined to the top surface layers, and the underlying layers preserved, it may be possible to explore new avenues in how to handle, prepare, and passivate future MnBi2Te4 devices.

Original language	English
Pages (from-to)	6102-6108
Number of pages	7
Journal	ACS Applied Materials & Interfaces
Volume	14
Issue number	4
DOIs	https://doi.org/10.1021/acsami.1c19089
Publication status	Published - 20 Jan 2022

Keywords

air stability
capping layer
magnetic topological insulator
MnBiTe
thin film

Access to Document

10.1021/acsami.1c19089

Cite this

@article{b05cf4d650614846a1a45f08a79a8fae,

title = "Formation of a Stable Surface Oxide in MnBi2Te4Thin Films",

abstract = "Understanding the air stability of MnBi2Te4 thin films is crucial for the development and long-term operation of electronic devices based on magnetic topological insulators. In the present work, we study MnBi2Te4 thin films upon exposure to the atmosphere using a combination of synchrotron-based photoelectron spectroscopy, room-temperature electrical transport, and atomic force microscopy to determine the oxidation process. After 2 days of air exposure, a 2 nm thick oxide passivates the surface, corresponding to the oxidation of only the top two surface layers, with the underlying layers preserved. This protective oxide layer results in samples that still exhibit metallic conduction even after several days of air exposure. Furthermore, the work function decreases from 4.4 eV for pristine MnBi2Te4 to 4.0 eV after the formation of the oxide, along with only a small shift in the core levels, indicating minimal doping as a result of air exposure. With the oxide confined to the top surface layers, and the underlying layers preserved, it may be possible to explore new avenues in how to handle, prepare, and passivate future MnBi2Te4 devices.",

keywords = "air stability, capping layer, magnetic topological insulator, MnBiTe, thin film",

author = "Golrokh Akhgar and Qile Li and {Di Bernardo}, Iolanda and Trang, {Chi Xuan} and Chang Liu and Ali Zavabeti and Julie Karel and Anton Tadich and Fuhrer, {Michael S.} and Edmonds, {Mark T.}",

note = "Funding Information: G.A., M.T.E., J.K., and M.S.F. acknowledge the funding support from the Australian Research Council Centre for Excellence Future Low Energy Electronics Technologies (CE170100039). M.T.E. acknowledges the support from ARC DECRA fellowship (DE160101157). This work was performed in part at the Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF). Part of this research was undertaken on the Soft X-ray beamline at the Australian Synchrotron, part of ANSTO. The authors acknowledge Prof. Steven Prawer and use of his laser cutter facility at the University of Melbourne in making the shadow masks. Publisher Copyright: {\textcopyright} 2022 American Chemical Society.",

year = "2022",

month = jan,

day = "20",

doi = "10.1021/acsami.1c19089",

language = "English",

volume = "14",

pages = "6102--6108",

journal = "ACS Applied Materials & Interfaces",

issn = "1944-8244",

publisher = "American Chemical Society",

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Formation of a Stable Surface Oxide in MnBi₂Te₄Thin Films. / Akhgar, Golrokh; Li, Qile; Di Bernardo, Iolanda; Trang, Chi Xuan; Liu, Chang; Zavabeti, Ali; Karel, Julie; Tadich, Anton; Fuhrer, Michael S.; Edmonds, Mark T.

In: ACS Applied Materials & Interfaces, Vol. 14, No. 4, 20.01.2022, p. 6102-6108.

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

TY - JOUR

T1 - Formation of a Stable Surface Oxide in MnBi2Te4Thin Films

AU - Akhgar, Golrokh

AU - Li, Qile

AU - Di Bernardo, Iolanda

AU - Trang, Chi Xuan

AU - Liu, Chang

AU - Zavabeti, Ali

AU - Karel, Julie

AU - Tadich, Anton

AU - Fuhrer, Michael S.

AU - Edmonds, Mark T.

N1 - Funding Information: G.A., M.T.E., J.K., and M.S.F. acknowledge the funding support from the Australian Research Council Centre for Excellence Future Low Energy Electronics Technologies (CE170100039). M.T.E. acknowledges the support from ARC DECRA fellowship (DE160101157). This work was performed in part at the Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF). Part of this research was undertaken on the Soft X-ray beamline at the Australian Synchrotron, part of ANSTO. The authors acknowledge Prof. Steven Prawer and use of his laser cutter facility at the University of Melbourne in making the shadow masks. Publisher Copyright: © 2022 American Chemical Society.

PY - 2022/1/20

Y1 - 2022/1/20

N2 - Understanding the air stability of MnBi2Te4 thin films is crucial for the development and long-term operation of electronic devices based on magnetic topological insulators. In the present work, we study MnBi2Te4 thin films upon exposure to the atmosphere using a combination of synchrotron-based photoelectron spectroscopy, room-temperature electrical transport, and atomic force microscopy to determine the oxidation process. After 2 days of air exposure, a 2 nm thick oxide passivates the surface, corresponding to the oxidation of only the top two surface layers, with the underlying layers preserved. This protective oxide layer results in samples that still exhibit metallic conduction even after several days of air exposure. Furthermore, the work function decreases from 4.4 eV for pristine MnBi2Te4 to 4.0 eV after the formation of the oxide, along with only a small shift in the core levels, indicating minimal doping as a result of air exposure. With the oxide confined to the top surface layers, and the underlying layers preserved, it may be possible to explore new avenues in how to handle, prepare, and passivate future MnBi2Te4 devices.

AB - Understanding the air stability of MnBi2Te4 thin films is crucial for the development and long-term operation of electronic devices based on magnetic topological insulators. In the present work, we study MnBi2Te4 thin films upon exposure to the atmosphere using a combination of synchrotron-based photoelectron spectroscopy, room-temperature electrical transport, and atomic force microscopy to determine the oxidation process. After 2 days of air exposure, a 2 nm thick oxide passivates the surface, corresponding to the oxidation of only the top two surface layers, with the underlying layers preserved. This protective oxide layer results in samples that still exhibit metallic conduction even after several days of air exposure. Furthermore, the work function decreases from 4.4 eV for pristine MnBi2Te4 to 4.0 eV after the formation of the oxide, along with only a small shift in the core levels, indicating minimal doping as a result of air exposure. With the oxide confined to the top surface layers, and the underlying layers preserved, it may be possible to explore new avenues in how to handle, prepare, and passivate future MnBi2Te4 devices.

KW - air stability

KW - capping layer

KW - magnetic topological insulator

KW - MnBiTe

KW - thin film

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U2 - 10.1021/acsami.1c19089

DO - 10.1021/acsami.1c19089

M3 - Article

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AN - SCOPUS:85123957071

VL - 14

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JO - ACS Applied Materials & Interfaces

JF - ACS Applied Materials & Interfaces

SN - 1944-8244

IS - 4

ER -

Formation of a Stable Surface Oxide in MnBi₂Te₄Thin Films

Abstract

Keywords

Access to Document

Other files and links

ARC Centre of Excellence in Future Low-energy Electronics Technologies

Realisation of novel electronic phases in two-dimensional materials

Australian Synchrotron

Cite this

Formation of a Stable Surface Oxide in MnBi2Te4Thin Films

Abstract

Keywords

Access to Document

Other files and links

Projects

ARC Centre of Excellence in Future Low-energy Electronics Technologies

Realisation of novel electronic phases in two-dimensional materials

Equipment

Australian Synchrotron

Cite this

Formation of a Stable Surface Oxide in MnBi₂Te₄Thin Films