论文标题
$ \ text {bifeo} _ \ text {3} $（001）表面的半金属和二维孔气
Half-metallicity and two-dimensional hole gas at the $\text{BiFeO}_\text{3}$(001) surface
论文作者
论文摘要
四方$ \ rm {Bifeo_3} $（001）表面的电子结构和热力学稳定性已使用密度函数理论进行了研究。在这项工作中，已经研究了具有具有两个可能表面终止的不同晶格常数的四个不同的结构。我们发现，表面电子结构和热力学稳定性相对于表面终止的性质非常敏感。 $ \ rm {feo_2} $终止表面在所有情况下与$ \ rm {biio} $相比，在所有情况下都更稳定。有趣的是，我们发现所有结构中一个单层厚的表面上有半金属性和自旋偏振的二维孔气（2DHG）的证据。表面厚度的效果已系统地研究。已经证明，半金属的2DHG仅在所有厚度的结构之一中生存，这是最热力学稳定的结构。
The electronic structure and thermodynamic stability of tetragonal $\rm{BiFeO_3}$(001) surfaces have been investigated using density functional theory. In this work, four different structures having different lattice constants with two possible surface terminations have been studied. We have found that the surface electronic structure and the thermodynamic stability is quite sensitive with respect to the nature of the surface termination. The $\rm{FeO_2}$ terminated surface is found to be energetically more stable compared to $\rm{BiO}$ terminated surface in all the cases. Interestingly, we have found evidences of half-metallicity and spin-polarized two-dimensional hole gas (2DHG) at the one mono-layer thick surface in all the structures. The effect of the surface thickness have been systematically studied. It has been demonstrated that the half-metallic 2DHG survives only in one of the structures for all the thicknesses, incidentally, which is the most thermodynamically stable structure.
