seed projects

Vlad Pribiag, Bharat Jalan: Electrostatic Gating of MBE-Grown Superconducting Complex Oxide Thin Films

Currently, there is no consensus on the nature of superconductivity in SrTiO₃ (STO) despite decades of work on this problem. One of the key challenges has been to separate the effects of disorder from those of the charge density. For example, doping with O vacancies or with Nb results in superconductivity domes centered at different charge densities. Chemical doping of STO alone cannot be used to separate between these two contributions since dopants affect both disorder and charge density. Our primary goal is to separate these two effects using electrostatic gating of Nd-doped STO thin films. With support from our previous seed, we showed that Nd-doped STO becomes superconducting at ~200 mK. A key interest for using Nd as the dopant is that it is a magnetic element. This will therefore simultaneously allow us to explore the role of spin-dependent scattering on STO superconductivity, by comparing with gated La-STO samples (La is not magnetic). To our knowledge, superconductivity has never before been observed in STO doped with a magnetic element (prior to our preliminary data).

Funded by the National Science Foundation through the University of Minnesota MRSEC under Award Number DMR-1420013