论文标题
MNBI $ _ {2} $ te $ _ {4} $中的磁性结构与表面状态之间的相互作用
Interplay between the magnetic structures and the surface states in MnBi$_{2}$Te$_{4}$ from first-principles studies
论文作者
论文摘要
抗铁磁性（AFM）拓扑绝缘子MNBI $ _ {2} $ te $ _ {4} $被认为具有拓扑表面状态（TSS）具有较大的带隙，这是由于表面上的铁磁（FM）订单，并且能够托管长期轴心的轴承状态。然而，最近的角度分辨光发射光谱（ARPES）实验表明TSS是无间隙的，与理论预测相矛盾。同时，一些实验表明，Mnbi $ _ {2} $ te $ _ {4} $的表面上有强大的面外FM订单。为了理解这些看似矛盾的结果，我们进行了全面的第一原理计算，以研究表面磁力和TSS之间的相互作用。我们的计算提供了直接的证据，表明在广泛的参数中，（几乎）无间隙的TSS可以与表面FM顺序共存，从而求解表面磁性和无间隙TSS的悖论。我们进一步表明，接近效应可能是一条有前途的途径，可以在Mnbi $ _ {2} $ te $ _ {4} $的TSS中打开差距。我们的研究加深了对表面磁和TSS之间关系的理解。
The antiferromagnetic (AFM) topological insulator MnBi$_{2}$Te$_{4}$ was believed to have a topological surface state (TSS) with large band gap due to the ferromagnetic (FM) order on the surface, and be able to host the long-sought axion states. However, recent angle-resolved photoemission spectroscopy (ARPES) experiments indicate that the TSS is gapless, contradicting the theoretical predictions. Meanwhile, several experiments have suggested that there is robust out-of-plane FM order on the surface of MnBi$_{2}$Te$_{4}$. To understand these seemingly contradictory results, we carry out comprehensive first-principles calculations to investigate the interplay between the surface magnetism and the TSS. Our calculations provide direct evidence that in a wide range of parameters, the (nearly) gapless TSS can coexist with the surface FM order, therefore solving the paradox of the surface magnetism and the gapless TSS. We further show that proximity effects can be a promising route to open the gap in the TSS of MnBi$_{2}$Te$_{4}$. Our research deepens the understanding of the relationship between surface magnetism and TSS.
