The electronic structure of a pulsed laser deposited epitaxial $\mathrm{La}\mathrm{V}{\mathrm{O}}_3$ (LVO) thin film grown on a $\mathrm{LaAl}{\mathrm{O}}_3$ (001) (LAO) substrate has been studied at room temperature and at 130 K, which is below the structural (141 K) and magnetic transition temperatures (143 K) of single-crystal LVO. Significant modification in spectral intensity, largely around the $\mathrm{V}3d\text{−}\mathrm{O}2p$ hybridized region, is observed in the valence band spectrum (VBS) of a LVO film at 130 K. Resonant photoemission study at 130 K confirms the presence of a charge-transfer screened $3d^n\underline{\mathrm{L}}$ ($\underline{\mathrm{L}}$: hole in the $\mathrm{O}2p$) final state along with the dominant $3d^{n-1}$ final state at 1.5 eV binding energy in the valence band. On the contrary, in the room temperature VBS, dominant $\mathrm{V}3d$ states with only the $3d^{n-1}$ kind of final state are accentuated. To understand this difference, density functional theory calculations are employed. The changes in crystal structure from room temperature orthorhombic to low temperature monoclinic ($M$ LVO) symmetry leads to remarkable change in the electronic structure around the Fermi level, including transition from the direct to the indirect nature of the band gap. Our calculations also confirm an enhanced $\mathrm{O}2p$ character in the valence band edge of $M$ LVO that is hybridized with $\mathrm{V}3d$. These results are further corroborated with octahedral distortions associated with the structural transition.

中文翻译：

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Mott绝缘子LaVO3薄膜的单斜相中增强的电荷转移特性

外延沉积的脉冲激光的电子结构 $啦\mathrm{V}{\mathrm{Ø}}_3$ （LVO）薄膜生长在 $\mathrm{拉铝}{\mathrm{Ø}}_3$（001）（LAO）基板已在室温和130 K下进行了研究，该温度低于单晶LVO的结构（141 K）和磁转变温度（143 K）。光谱强度发生重大变化，主要在$\mathrm{V}3d\text{-}\mathrm{Ø}2p$ LVO薄膜在130 K的价带谱（VBS）中观察到杂化区域。在130 K的共振光发射研究证实了电荷转移的存在 $3d^{ñ}\underline{\mathrm{大号}}$ （$\underline{\mathrm{大号}}$：孔中 $\mathrm{Ø}2p$）最终状态以及优势 $3d^{ñ-\mathrm{1个}}$价带中1.5 eV的结合能的最终状态。相反，在室温下，VBS占主导地位$\mathrm{V}3d$ 仅具有 $3d^{ñ-\mathrm{1个}}$最终状态的强调。为了理解这种差异，采用密度泛函理论计算。晶体结构从室温斜方晶到低温单斜晶（$\mathrm{中号}$LVO）对称性导致费米能级附近的电子结构发生显着变化，包括从带隙的直接性质转换为间接性质。我们的计算还证实了$\mathrm{Ø}2p$ 价带边缘的字符 $\mathrm{中号}$ 与LVO杂交的LVO $\mathrm{V}3d$。这些结果与与结构转变相关的八面体变形进一步得到证实。