Control of Epitaxial BaFe2As2 Atomic Configurations with Substrate Surface Terminations

Jong Hoon Kang, Lin Xie, Yi Wang, Hyungwoo Lee, Neil Campbell, Jianyi Jiang, Philip J. Ryan, David J. Keavney, Jung Woo Lee, Tae Heon Kim, Xiaoqing Pan, Long Qing Chen, Eric E. Hellstrom, Mark S. Rzchowski, Zi Kui Liu, Chang Beom Eom

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Atomic layer controlled growth of epitaxial thin films of unconventional superconductors opens the opportunity to discover novel high temperature superconductors. For instance, the interfacial atomic configurations may play an important role in superconducting behavior of monolayer FeSe on SrTiO3 and other Fe-based superconducting thin films. Here, we demonstrate a selective control of the atomic configurations in Co-doped BaFe2As2 epitaxial thin films and its strong influence on superconducting transition temperatures by manipulating surface termination of (001) SrTiO3 substrates. In a combination of first-principles calculations and high-resolution scanning transmission electron microscopy imaging, we show that Co-doped BaFe2As2 on TiO2-terminated SrTiO3 is a tetragonal structure with an atomically sharp interface and with an initial Ba layer. In contrast, Co-doped BaFe2As2 on SrO-terminated SrTiO3 has a monoclinic distortion and a BaFeO3-x initial layer. Furthermore, the superconducting transition temperature of Co-doped BaFe2As2 ultrathin films on TiO2-terminated SrTiO3 is significantly higher than that on SrO-terminated SrTiO3, which we attribute to shaper interfaces with no lattice distortions. This study allows the design of the interfacial atomic configurations and the effects of the interface on superconductivity in Fe-based superconductors.

Original languageEnglish (US)
Pages (from-to)6347-6352
Number of pages6
JournalNano letters
Volume18
Issue number10
DOIs
StatePublished - Oct 10 2018

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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