Dimensionality reduction induced metal-insulator transitions in oxide heterostructures are usually coupled with structural and magnetic phase transitions, which complicate the interpretation of the underlying physics. Therefore, achieving isostructural MIT is of great importance for fundamental physics and even more for applications. Here, we report an isostructural metal-insulator transition driven by dimensional-crossover in spin-orbital coupled ${\mathrm{SrIrO}}_3$ films. By using in situ pulsed laser deposition and angle-resolved photoemission spectroscopy, we synthesized and investigated the electronic structure of ${\mathrm{SrIrO}}_3$ ultrathin films with atomic-layer precision. Through inserting orthorhombic ${\mathrm{CaTiO}}_3$ buffer layers, combined low-energy electron diffraction measurements and first-principles density functional theory calculations show that the crystal structure of ${\mathrm{SrIrO}}_3$ films remains bulklike with similar oxygen octahedra rotation and tilting when approaching the ultrathin limit. We observe that a dimensional-crossover metal-insulator transition occurs in isostructural ${\mathrm{SrIrO}}_3$ films. Intriguingly, we find the bandwidth of $J_{\mathrm{eff}}=3/2$ states reduces with lowering the dimensionality and drives the metal-insulator transition. Our results establish a bandwidth controlled metal-insulator transition in the isostructural ${\mathrm{SrIrO}}_3$ thin films.

中文翻译：

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由尺寸交叉 inSrIrO3 异质结构驱动的同构金属-绝缘体转变

氧化物异质结构中的降维引起的金属-绝缘体转变通常与结构和磁性相变相结合，这使对基础物理的解释变得复杂。因此，实现等结构 MIT 对基础物理学乃至应用而言都具有重要意义。在这里，我们报告了由自旋轨道耦合中的尺寸交叉驱动的同构金属 - 绝缘体转变${锶}_3$电影。通过使用原位脉冲激光沉积和角分辨光电子能谱，我们合成并研究了电子结构${锶}_3$具有原子层精度的超薄膜。通过插入斜方${\mathrm{钙钛矿}}_3$缓冲层，结合低能电子衍射测量和第一性原理密度泛函理论计算表明，${锶}_3$当接近超薄极限时，薄膜仍保持块状，具有类似的氧八面体旋转和倾斜。我们观察到尺寸交叉金属绝缘体转变发生在同构${锶}_3$电影。有趣的是，我们发现带宽为${Ĵ}_{\mathrm{效果}}=3/2$状态随着维度的降低而降低并驱动金属 - 绝缘体转变。我们的结果在等结构中建立了带宽控制的金属绝缘体转变${锶}_3$薄膜。