论文标题
从第一原理计算中，jahn-teller驱动的金属绝缘体过渡的证据
Evidence for Jahn-Teller-driven metal-insulator transition in strained SrCrO3 from first principles calculations
论文作者
论文摘要
使用密度功能理论（DFT）及其扩展到DFT+$ u $，我们提出了一种可能的情况，用于应变诱导的金属绝缘体过渡，最近在Srcro $ _3 $的薄膜中报道了。金属 - 绝缘体的转变涉及与相关稀土糊状物相似的Jahn-Teller（JT）失真的出现，后者也表现出了标称的$ d^2 $占用过渡金属阳离子的职业。我们的计算表明，对于Hubbard $ u $参数的现实值，未经培训的系统展示了C型反铁磁性有序的基态，这已经接近JT不稳定。但是，$ d_ {xz} $/$ d_ {yz} $ band的较大的能量重叠使JT失真的出现不利于，较低的说谎$ d_ {xy} $ band。拉伸外延菌株降低了$ d_ {xy} $ band相对于$ d_ {xz} $/$ d_ {yz} $的能量，从而使系统更接近$ d_ {xy}^1（d_ {xz} d_ {xz} d_ {yz} d_ {yz}）^1 $ $。然后，JT失真将$ d_ {xz} $和$ d_ {yz} $ orbitals的变性上升，从而允许在电子频段结构中张开差距。
Using density-functional theory (DFT) and its extension to DFT+$U$, we propose a possible scenario for a strain-induced metal-insulator transition which has been reported recently in thin films of SrCrO$_3$. The metal-insulator transition involves the emergence of a Jahn-Teller (JT) distortion similar to the case of the related rare-earth vanadates, which also exhibit a nominal $d^2$ occupation of the transition metal cation. Our calculations indicate that, for realistic values of the Hubbard $U$ parameter, the unstrained system exhibts a C-type antiferromagnetically ordered ground state, that is already rather close to a JT instability. However, the emergence of the JT distortion is disfavored by the large energetic overlap of the $d_{xz}$/$d_{yz}$ band with the lower lying $d_{xy}$ band. Tensile epitaxial strain lowers the energy of the $d_{xy}$ band relative to $d_{xz}$/$d_{yz}$ and thus brings the system closer to the nominal filling of $d_{xy}^1(d_{xz}d_{yz})^1$. The JT distortion then lifts the degeneracy between the $d_{xz}$ and $d_{yz}$ orbitals and thus allows to open up a gap in the electronic band structure.
