钙钛矿钌酸钙(CaRuO3)是典型的多轨道4d过渡金属氧化物，一般认为其电子关联性来源于洪德耦合与电子在位库伦排斥的共同作用。由于钌酸钙有很大的晶格畸变(Ru-O-Ru键角只有~150°)，其电子关联被大大增强同时产生了一些有趣的电磁性质，比如它在低温下的费米液体输运行为被极大地抑制，并且其磁性对键角非常敏感（处在磁性边界点上）。我们提出利用界面结构重组和量子束缚效应来调控钌酸钙薄膜中的电子关联。我们期望通过精确解析钌氧键长键角的变化，测量电子能带结构和质量重组，同时辅助测量相关的电磁性质，建立起钌酸钙中晶格畸变，电子结构（电子关联）和电磁性质的关系。通过对薄膜不同厚度的系统研究，我们也将探索关联4d电子形成的量子阱效应以及在严格二维束缚下电子关联的变化。

Perovskite CaRuO3 is a prototypical multiorbital 4d transition metal oxides. It is generally believed that its electronic correlation arises from interplay between Hund’s coupling and onsite coulomb repulsion. Due to the strong lattice distortion (Ru-O-Ru bond angle is ~150°), its electronic correlation is largely enhanced and gives rise to some interesting electromagnetic properties. For example, its Fermi liquid behavior is strongly suppressed at even very low temperature and its magnetic ground state is strongly dependent on the Ru-O-Ru bond angle, i.e., close to a magnetic instability point. We propose to study the electron correlations in CaRuO3 by interfacial structural modifications and quantum confinement. Combing high-precision structural probes, direct measurement of electronic structure and complementary studies of electromagnetic properties, we hope to establish the connections between lattice distortions, electronic correlation and macroscopic electromagnetic properties. Through systematic thickness study, we will also explore the quantum size effects derived from correlated 4d electrons, particularly in the extreme two-dimensional limit.