Evolution of Mn1−xGexBi2Te4 Electronic Structure under Variation of Ge Content

Estyunina, Tatiana P.; Shikin, Alexander M.; Estyunin, Dmitry A.; Eryzhenkov, Alexander V.; Klimovskikh, Ilya I.; Bokai, Kirill A.; Golyashov, Vladimir A.; Kokh, Konstantin A.; Tereshchenko, Oleg E.; Kumar, Shiv; Shimada, Kenya; Tarasov, Artem V.

doi:10.3390/nano13142151

Open AccessArticle

Evolution of Mn_1−xGe_xBi₂Te₄ Electronic Structure under Variation of Ge Content

by

Tatiana P. Estyunina

^1,*,

Alexander M. Shikin

^1,*

,

Dmitry A. Estyunin

¹

,

Alexander V. Eryzhenkov

¹

,

Ilya I. Klimovskikh

²

,

Kirill A. Bokai

¹

,

Vladimir A. Golyashov

^1,3,4

,

Konstantin A. Kokh

^1,5

,

Oleg E. Tereshchenko

^1,3,4

,

Shiv Kumar

⁶,

Kenya Shimada

⁶

and

Artem V. Tarasov

¹

Department of Physics, Saint Petersburg State University, St. Petersburg 198504, Russia

²

Donostia International Physics Center, 20018 Donostia-San Sebastián, Spain

³

Synchrotron Radiation Facility SKIF, Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Kol’tsovo 630559, Russia

⁴

Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia

⁵

Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia

⁶

Hiroshima Synchrotron Radiation Center, Hiroshima University, Hiroshima 739-0046, Japan

^*

Authors to whom correspondence should be addressed.

Nanomaterials 2023, 13(14), 2151; https://doi.org/10.3390/nano13142151

Submission received: 30 June 2023 / Revised: 22 July 2023 / Accepted: 23 July 2023 / Published: 24 July 2023

(This article belongs to the Special Issue Advances in Topological Materials: Fundamentals, Challenges and Outlook, Volume II)

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Abstract

One of the approaches to manipulate MnBi

_{2}

Te

_{4}

properties is the magnetic dilution, which inevitably affects the interplay of magnetism and band topology in the system. In this work, we carried out angle-resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations for analysing changes in the electronic structure of Mn

_{1 - x}

Ge

_{x}

Bi

_{2}

Te

_{4}

that occur under parameter x variation. We consider two ways of Mn/Ge substitution: (i) bulk doping of the whole system; (ii) surface doping of the first septuple layer. For the case (i), the experimental results reveal a decrease in the value of the bulk band gap, which should be reversed by an increase when the Ge concentration reaches a certain value. Ab-initio calculations show that at Ge concentrations above 50%, there is an absence of the bulk band inversion of the Te

p_{z}

and Bi

p_{z}

contributions at the

Γ

-point with significant spatial redistribution of the states at the band gap edges into the bulk, suggesting topological phase transition in the system. For case (ii) of the vertical heterostructure Mn

_{1 - x}

Ge

_{x}

Bi

_{2}

Te

_{4}

/MnBi

_{2}

Te

_{4}

, it was shown that an increase of Ge concentration in the first septuple layer leads to effective modulation of the Dirac gap in the absence of significant topological surface states of spatial redistribution. The results obtained indicate that surface doping compares favorably compared to bulk doping as a method for the Dirac gap value modulation.

Keywords: magnetic topological insulator; topological surface states; electronic structure; topological phase transition; topological vertical heterostructure; ARPES; ab-initio calculations

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MDPI and ACS Style

Estyunina, T.P.; Shikin, A.M.; Estyunin, D.A.; Eryzhenkov, A.V.; Klimovskikh, I.I.; Bokai, K.A.; Golyashov, V.A.; Kokh, K.A.; Tereshchenko, O.E.; Kumar, S.; et al. Evolution of Mn_1−xGe_xBi₂Te₄ Electronic Structure under Variation of Ge Content. Nanomaterials 2023, 13, 2151. https://doi.org/10.3390/nano13142151

AMA Style

Estyunina TP, Shikin AM, Estyunin DA, Eryzhenkov AV, Klimovskikh II, Bokai KA, Golyashov VA, Kokh KA, Tereshchenko OE, Kumar S, et al. Evolution of Mn_1−xGe_xBi₂Te₄ Electronic Structure under Variation of Ge Content. Nanomaterials. 2023; 13(14):2151. https://doi.org/10.3390/nano13142151

Chicago/Turabian Style

Estyunina, Tatiana P., Alexander M. Shikin, Dmitry A. Estyunin, Alexander V. Eryzhenkov, Ilya I. Klimovskikh, Kirill A. Bokai, Vladimir A. Golyashov, Konstantin A. Kokh, Oleg E. Tereshchenko, Shiv Kumar, and et al. 2023. "Evolution of Mn_1−xGe_xBi₂Te₄ Electronic Structure under Variation of Ge Content" Nanomaterials 13, no. 14: 2151. https://doi.org/10.3390/nano13142151

APA Style

Estyunina, T. P., Shikin, A. M., Estyunin, D. A., Eryzhenkov, A. V., Klimovskikh, I. I., Bokai, K. A., Golyashov, V. A., Kokh, K. A., Tereshchenko, O. E., Kumar, S., Shimada, K., & Tarasov, A. V. (2023). Evolution of Mn_1−xGe_xBi₂Te₄ Electronic Structure under Variation of Ge Content. Nanomaterials, 13(14), 2151. https://doi.org/10.3390/nano13142151

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Evolution of Mn_1−xGe_xBi₂Te₄ Electronic Structure under Variation of Ge Content

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