α-MnTe, an A-type collinear antiferromagnet, has recently attracted significant attention due to its pronounced spin splitting despite having net zero magnetization, a phenomenon unique for a new class of magnetism dubbed altermagnetism. In this work, we develop a minimal effective Hamiltonian for MnTe based on realistic orbitals near the Fermi level at both the Γ and A points based on group representation theory, first-principles calculations, and tight-binding modeling. The Hamiltonian exhibits qualitatively distinct electron transport characteristics between these high-symmetry points and for different in-plane Néel vector orientations along the <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41535_2025_784_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="42" /> </InlineMediaObject> <EquationSource Format="TEX">$[11\bar{2}0]$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>[</mo> <mrow> <mn>11</mn> <mover accent="true"> <mrow> <mn>2</mn> </mrow> <mo>¯</mo> </mover> <mn>0</mn> </mrow> <mo>]</mo> </mrow> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41535_2025_784_Article_IEq2.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="42" /> </InlineMediaObject> <EquationSource Format="TEX">$[1\bar{1}00]$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>[</mo> <mrow> <mn>1</mn> <mover accent="true"> <mrow> <mn>1</mn> </mrow> <mo>¯</mo> </mover> <mn>00</mn> </mrow> <mo>]</mo> </mrow> </math></EquationSource> </InlineEquation> directions. Although the spin–orbit coupling (SOC) is believed to be not important in altermagnets, we show the dominant role of SOC in the spin splitting and valence electrons of MnTe. These findings provide critical insights into altermagnetic electron transport in MnTe and establish a model playground for future theoretical and experimental studies.

Symmetry and minimal Hamiltonian of nonsymmorphic collinear antiferromagnet MnTe

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2025年7月1日

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Koichiro Takahashi,
Hong-Fei Huang,
Jie-Xiang Yu,
Jiadong Zang

摘要

α-MnTe, an A-type collinear antiferromagnet, has recently attracted significant attention due to its pronounced spin splitting despite having net zero magnetization, a phenomenon unique for a new class of magnetism dubbed altermagnetism. In this work, we develop a minimal effective Hamiltonian for MnTe based on realistic orbitals near the Fermi level at both the Γ and A points based on group representation theory, first-principles calculations, and tight-binding modeling. The Hamiltonian exhibits qualitatively distinct electron transport characteristics between these high-symmetry points and for different in-plane Néel vector orientations along the $[11\bar{2}0]$ $[11 \bar{2} 0]$ and $[1\bar{1}00]$ $[1 \bar{1} 00]$ directions. Although the spin–orbit coupling (SOC) is believed to be not important in altermagnets, we show the dominant role of SOC in the spin splitting and valence electrons of MnTe. These findings provide critical insights into altermagnetic electron transport in MnTe and establish a model playground for future theoretical and experimental studies.