Faculty Host: Masha Kamenetska
Student Host: Brent Lawson
Refreshments at 2:45 PM
Title: Nanoscale Synthesis and Characterization of Superconducting Topological Materials
Bringing two different materials in close proximity to one another can lead to the emergence of novel electronic phenomena. We use molecular beam epitaxy to create heterostructures of topological insulators (Bi2Te3 and SnTe) and high-temperature superconductors (Fe(Te,Se) and cuprate Bi2Sr2CaCu2O8+x) with atomic-scale control. Using low-temperature scanning tunneling microscopy and spectroscopy, we characterize surface electronic properties. On the surfaces of Bi2Te3 and SnTe grown on Fe(Te,Se), we detect an induced superconducting gap as high as ~3.5 meV, which is the largest reported gap induced by proximity to an s-wave superconductor to-date. We contrast this observation with the lack of induced superconductivity when cuprate Bi2Sr2CaCu2O8+x is used as the substrate. We conclude by discussing the implications of our results on the potential emergence of topological superconductivity and Majorana fermions in these systems.
Ilija Zeljkovic obtained a Ph.D. in Physics from Harvard University in 2013. Following a two-year post-doctoral appointment with Prof. Vidya Madhavan during which he worked on thin film synthesis and characterization of topological materials, he started as an Assistant Professor of Physics at Boston College in 2015. His current research focuses on molecular beam epitaxy (MBE) synthesis and scanning tunneling microscopy/spectroscopy (STM/S) characterization of quantum materials, including unconventional superconductors, topological materials and oxides. He is the recipient of DARPA Young Faculty Award (2017), NSF CAREER Award (2017), ARO Young Investigator Award (2017) and DOE Early Career Award (2019).