Interlayer coupling effects between high mobility two-dimensional superconductors are studied in bilayer delta-doped SrTiO3 heterostructures. By tuning the undoped SrTiO3 spacer layer between the dopant planes, clear tunable coupling is demonstrated in the variation of the sheet carrier density, Hall mobility, superconducting transition temperature, and the temperature- and angle-dependences of the superconducting upper critical field. Systematic variation is found between one effective (merged) two-dimensional superconductor to two decoupled two-dimensional superconductors. In the intermediate coupled regime, a crossover is observed due to coupling arising from inter-sub-band interactions.
@article{arxiv.1308.2215,
title = {Tunable Coupling of Two-Dimensional Superconductors in Bilayer SrTiO3 Heterostructures},
author = {Hisashi Inoue and Minu Kim and Christopher Bell and Yasuyuki Hikita and Srinivas Raghu and Harold Y. Hwang},
journal= {arXiv preprint arXiv:1308.2215},
year = {2013}
}