Intrinsic even-odd thickness-driven anomalous Hall effect in epitaxial <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>MnBi</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi>Te</mml:mi> <mml:mn>4</mml:

We demonstrate precise control of magnetism in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ thin films through careful synthesis by molecular beam epitaxy, achieving minimal defects and accurate layer thickness control. By optimizing Mn-Bi-Te ratios and growth temperatures, we minimize detrimental self-doping effects and accurately target integer-layer films. X-ray diffraction and reflectivity provide quantitative measures of film quality and thickness. When these macroscale probes of structure and thickness are integrated with magnetotransport measurements, a striking even-odd layer dependence of the anomalous Hall effect is revealed. Odd-layer films exhibit a large hysteresis up to the N\'eel temperature ($\ensuremath{\sim}25\phantom{\rule{0.16em}{0ex}}\mathrm{K}$), consistent with noncompensated antiferromagnetism, while even-layer films show minimal response, as expected for an antiferromagnet. The sign of the anomalous Hall effect exhibits a sign reversal for intrinsic magnetism versus magnetism associated with defects. This work identifies critical factors for inducing pure, noncompensated ferromagnetism and reveals the characteristics of the intrinsic anomalous Hall effect in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$, which together is a step toward realizing the zero-field quantum anomalous Hall effect in topological materials.

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Publication Details

Journal
Physical Review Materials
Published
2026-04-21
DOI
https://doi.org/10.1103/pqj7-prc1
Primary Topic
Topological Materials and Phenomena
Type
article
Field-Weighted Citation Impact
0.00

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article

Intrinsic even-odd thickness-driven anomalous Hall effect in epitaxial <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>MnBi</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi>Te</mml:mi> <mml:mn>4</mml:

Thomas Z. Ward, S Kim, Debarghya Mallick, Yue Cao et al.
Physical Review Materials
Topological Materials and Phenomena
article

Intrinsic even-odd thickness-driven anomalous Hall effect in epitaxial <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>MnBi</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi>Te</mml:mi> <mml:mn>4</mml:

Thomas Z. Ward, S Kim, Debarghya Mallick, Yue Cao, Gabriel A. Vázquez-Lizardi, H. Miao, Matthew Brahlek, Alessandro R. Mazza, Danielle Reifsnyder Hickey, An‐Hsi Chen, Liang Wu, Christopher Nelson, Gyula Eres, Robert G. Moore, Debangshu Mukherjee
article en

Abstract

We demonstrate precise control of magnetism in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ thin films through careful synthesis by molecular beam epitaxy, achieving minimal defects and accurate layer thickness control. By optimizing Mn-Bi-Te ratios and growth temperatures, we minimize detrimental self-doping effects and accurately target integer-layer films. X-ray diffraction and reflectivity provide quantitative measures of film quality and thickness. When these macroscale probes of structure and thickness are integrated with magnetotransport measurements, a striking even-odd layer dependence of the anomalous Hall effect is revealed. Odd-layer films exhibit a large hysteresis up to the N\'eel temperature ($\ensuremath{\sim}25\phantom{\rule{0.16em}{0ex}}\mathrm{K}$), consistent with noncompensated antiferromagnetism, while even-layer films show minimal response, as expected for an antiferromagnet. The sign of the anomalous Hall effect exhibits a sign reversal for intrinsic magnetism versus magnetism associated with defects. This work identifies critical factors for inducing pure, noncompensated ferromagnetism and reveals the characteristics of the intrinsic anomalous Hall effect in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$, which together is a step toward realizing the zero-field quantum anomalous Hall effect in topological materials.

Physical Review MaterialsVol. 10(4)
Argonne National Laboratory (US), Oak Ridge National Laboratory (US), Pennsylvania State University (US), Los Alamos National Laboratory (US), California University of Pennsylvania (US)
U.S. Department of Energy, Office of Science, National Nuclear Security Administration, College of Earth and Mineral Sciences, Pennsylvania State University, Basic Energy Sciences, Army Research Office, Oak Ridge National Laboratory, Los Alamos National Laboratory
Openalex Percentile: Top 11%
Topological Materials and Phenomena
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