EAPSI: Investigating superconductivity in ultrathin materials

超导体是一种能使电流无阻力流动的材料。然而，这些材料必须冷却到低温才能表现出这种特性。室温下的超导性将极大地改善生活的许多方面；长距离电力传输、医疗成像和运输只是其中的几个例子。这个项目将探索在不同材料之间的界面或“接触区”超导的可能性，通过采用一种技术，允许原子光滑界面的生长，称为分子束外延（MBE）。在台湾中央研究院李伟力博士的指导下，将使用专门用于氧化材料生长的MBE。分子束外延是一种允许原子层接层地生长材料的技术。这使得传统固态方法无法获得的新材料得以生长，也可以观察到块状材料中可能不存在的新现象。近年来，由于多次观察到Tc显著升高，薄膜材料中的界面超导性引起了人们的极大兴趣。通过界面机制被认为具有超导性的材料包括FeSe薄膜、re掺杂CaFe2As2、Sr2RuO4-Ru共晶体系和LaAlO3/SrTiO3 （LAO/STO）。在LAO/STO中，超导性出现在两个绝缘体之间的界面上。该项目将通过使用氧化物分子束外延（MBE）系统来生长材料，重点研究LAO / STO系统，探索界面的作用。本项目旨在表征生长薄膜的晶体结构和物理性质，以便更好地了解该系统和其他系统的超导性质。​

A superconductor is a type of material that allows electricity to flow without any resistance. However, these materials have to be cooled down to low temperatures before they can exhibit this property. Superconductivity at room temperature would vastly improve many aspects of life; long distance power transmission, medical imaging, and transportation are just a few examples. This project will explore the possibility of superconductivity at the interface, or "meeting area", between different materials by employing a technique that allows for the growth of atomically smooth interfaces, called Molecular Beam Epitaxy (MBE). A specialized MBE for the growth of oxide materials will be used under the guidance of Dr. Wei-Li Lee at Academia Sinica in Taiwan.Molecular Beam Epitaxy is a technique that allows for atomic layer-by-layer growth of materials. This allows growth of novel materials that would otherwise be inaccessible by traditional solid state methods, as well as the observation of new phenomena that may not be present in bulk materials. Recently, interfacial superconductivity in thin film materials has gained great interest due to several observations of significantly elevated Tc. Materials thought to be superconducting via an interfacial mechanism include FeSe thin films, RE-doped CaFe2As2, the Sr2RuO4-Ru eutectic system, and LaAlO3/SrTiO3 (LAO/STO). In LAO/STO, superconductivity arises at the interface between two insulators. This project will probe the role of the interface by employing an oxide Molecular Beam Epitaxy (MBE) system to grow materials with a focus on the LAO / STO system. This project aims to characterize the crystal structures as well as the physical properties of the grown films in order to better understand the nature of the superconductivity in this system and others. This NSF EAPSI award is funded in collaboration with the National Science Council of Taiwan.