Native defects in antiferromagnetic topological insulator <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:mn></mml:msub></mml:mrow></mml:math>
Zengle Huang, Mao-Hua Du, Jiaqiang Yan, Weida Wu
Abstract
Using scanning tunneling microscopy and spectroscopy, we visualized the native defects in antiferromagnetic topological insulator ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$. Two native defects, ${\mathrm{Mn}}_{\mathrm{Bi}}$ and ${\mathrm{Bi}}_{\mathrm{Te}}$ antisites, can be well resolved in the topographic images. ${\mathrm{Mn}}_{\mathrm{Bi}}$ tend to suppress the density of states at the conduction band edge. Spectroscopy imaging reveals a localized peaklike local density of state at $\ensuremath{\sim}80$ meV below the Fermi energy. A careful inspection of topographic and spectroscopic images, combined with density functional theory calculation, suggests this results from ${\mathrm{Bi}}_{\mathrm{Mn}}$ antisites at Mn sites. The random distribution of ${\mathrm{Mn}}_{\mathrm{Bi}}$ and ${\mathrm{Bi}}_{\mathrm{Mn}}$ antisites results in spatial fluctuation of local density of states near the Fermi level in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$.