Bimodal Phase Diagram of the Superfluid Density in LaAlO_{3}/SrTiO_{3} Revealed by an Interfacial Waveguide Resonator

• Published in: Physical review letters Vol. 122; no. 3; p. 036801
• Main Authors: Manca, Nicola, Bothner, Daniel, Monteiro, Ana M R V L, Davidovikj, Dejan, Sağlam, Yildiz G, Jenkins, Mark, Gabay, Marc, Steele, Gary A, Caviglia, Andrea D
• Format: Journal Article
• Language: English
• Published: United States 25.01.2019
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.122.036801

We explore the superconducting phase diagram of the two-dimensional electron system at the LaAlO_{3}/SrTiO_{3} interface by monitoring the frequencies of the cavity modes of a coplanar waveguide resonator fabricated in the interface itself. We determine the phase diagram of the superconducting transition as a function of the temperature and electrostatic gating, finding that both the superfluid density and the transition temperature follow a dome shape but that the two are not monotonically related. The ground state of this two-dimensional electron system is interpreted as a Josephson junction array, where a transition from long- to short-range order occurs as a function of the electronic doping. The synergy between correlated oxides and superconducting circuits is revealed to be a promising route to investigate these exotic compounds, complementary to standard magnetotransport measurements.