High Temperature, Topological Superconductivity via the Proximity Effect

点击翻译按钮获取中文摘要

Non-Technical AbstractThis award from the Condensed Matter Physics program of the Division of Materials Research supports Boston University with a project to explore new approach to induce superconductivity in a material using a recently developed proximity technique. Superconductivity, a state of matter in which electrons carry electricity without friction, occurs when a material is cooled below a certain critical temperature. Superconducting states, with relatively "high" transition temperatures (just above that of liquid nitrogen), can be induced by changing the chemistry of a series of magnetic materials. However, this involves changing multiple parameters simultaneously, complicating the analysis. This project follows an alternative approach which is to induce superconductivity via "proximity", namely placing a superconductor in excellent contact with a non-superconducting (normal) material, where the interface and normal state properties can be tuned. The project explores the various aspects of the normal materials that control the emergence of the proximity induced superconducting state. This will enable systematic studies and provide a platform for pursuing the elusive Majorana fermions. To achieve this students of all levels, high school to postdoctoral trainees, will learn a variety of technical (device fabrication and characterization) to professional skills (training, project management). Technical AbstractThis project is to generate new states of matter, while pushing the boundaries of our knowledge on the coupling of order parameters and topology. This will be achieved using a new mechanical bonding technique developed by the principal investigator, which opens the door to creating and manipulating unconventional superconductivity in semiconductors, semimetals and topological insulators. These new platforms will be explored using a combination of optical and transport techniques to address fundamental questions and technical challenges such as: What are the optimum conditions for observing a high Tc superconducting proximity effect? How do band structure, carrier density and topology affect the emergence of superconductivity? How is the symmetry of the superconducting order parameter affected by the host material? Particular focus will be given to the high temperature superconductor Bi2Sr2CaCu2O(8+y) in combination with MoS2, Bi2Te2Se, and Graphite/Graphene. Trainees at all levels will be involved in the fabrication of devices and the analysis of optical/differential conductance data, to learn a variety of analysis, device fabrication and characterization techniques, as well as professional skills.