Electron-Phonon Coupling and Dilute Superconductivity in SrTiO<sub>3</sub>
· Invited
Abstract
The nature of superconductivity in the dilute semiconductor SrTiO3 has remained an open question for over half a century. Thin film heterostructures provide new opportunities to examine SrTiO3 superconductivity using a newly developed method for engineering band alignments at oxide interfaces to access the electronic structure of Nb-doped SrTiO3 using high-resolution tunneling spectroscopy. While we observe strong coupling to the highest-energy longitudinal optic phonon consistent with λ ~ 1, the superconducting gap is found to be in the weak-coupling limit of BCS theory, i.e. λBCS~ 0.1. This discrepancy arises in the context of an unusual anti-adiabatic condition for superconductivity in SrTiO3 (Fermi energy < Debye energy), which we find precisely bounds the superconducting dome.
This work was done in collaboration with Hyeok Yoon, Adrian Swartz, Hisashi Inoue, Yasuyuki Hikita, and Sri Raghu.
This work was done in collaboration with Hyeok Yoon, Adrian Swartz, Hisashi Inoue, Yasuyuki Hikita, and Sri Raghu.
*This work was supported by the Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract No. DE-AC02-76SF00515; and by the Gordon and Betty Moore Foundations Emergent Phenomena in Quantum Systems Initiative through Grant GBMF4415.
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Presenters
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Harold Hwang
- Institute for Materials and Energy Sciences, Stanford University
- Stanford University
- Department of Applied Physics, Stanford University
- Applied Physics, Stanford University
- SIMES, SLAC
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- SLAC National Accelerator Lab.
- Physics, Stanford University
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory