氧化物表面二维电子液体中多体相互作用的调控研究

Electron-phonon and electron-plasmon interactions, among the most important many-body interactions in condensed matter physics, play important roles in a diverse array of phenomena. Recently, the long-range electron-phonon interaction has attracted tremendous attention both in experimental and theoretical studies, due to the discovery of the dramatic enhancement of the superconducting transition temperature in FeSe/SrTiO3. Thus, it is of great importance to study directly the many-body interaction between electron, phonon and plasmon for understanding interface superconductivity. The two-dimensional electron liquid (2DEL) formed at oxide surfaces shows tunable carrier density in a large range, as well as strong and anisotropic electron-phonon coupling. Thus, it serves as an ideal platform to investigate the electron-phonon and electron-plasmon interactions using angle-resolved photoemission spectroscopy (ARPES). In this project, we propose to perform ARPES investigation of the band structure on oxide surfaces. By analyzing the data, we expect to determine their coupling nature and strength. Furthermore, we plan to investigate their evolution by tuning the carrier density, and investigate the anisotropic interactions by engineering crystalline orientation. We expect our results have important implications on the oxide interface.

电子-声子及电子-等离激元相互作用是凝聚态物理中非常重要的多体相互作用,对材料的热力学、电学和光学性质等都起着至关重要的影响。最近，研究发现长程的电子-声子相互作用，对界面超导具有巨大的增强作用。因此，直接研究材料的电子、声子及等离激元等多体相互作用对理解界面超导等性质具有重要的意义。本项目利用氧化物表面二维电子液体的电荷密度大范围可调、电子-声子耦合强度大及各向异性明显等特点，通过角分辨光电子能谱测量其能带结构及其随电荷密度的演化，定量解析出电子-声子及电子-等离激元耦合类型、强度及其演化规律。我们的结果将为理解氧化物界面的物理性质奠定基础。

电子-声子及电子-等离激元相互作用是凝聚态物理中非常重要的多体相互作用,对材料的磁电性质等都起着至关重要的影响。最近，研究发现长程的电子-声子相互作用，对界面超导具有巨大的增强作用。因此，直接研究材料的电子、声子及等离激元等多体相互作用对理解氧化物界面超导等性质具有重要的意义。本项目通过角分辨光电子能谱测量氧化物测量氧化物表界面磁电性质，解析其能带结构及薄膜维度的演化，确定了氧化物体系的金属-绝缘体相变机理、磁性外尔费米子及各向异性的电荷-自旋转换等。本项目的结果将为理解氧化物界面的磁电性质奠定基础。