Anisotropy of upper critical fields and interface superconductivity in FeSe/SrTiO3grown by PLD

Tomoki Kobayashi; Hiroki Nakagawa; Hiroki Ogawa; Fuyuki Nabeshima; Atsutaka Maeda

doi:10.1088/1361-648X/ace410

Anisotropy of upper critical fields and interface superconductivity in FeSe/SrTiO₃grown by PLD

J Phys Condens Matter. 2023 Jul 14;35(41). doi: 10.1088/1361-648X/ace410.

Authors

Tomoki Kobayashi¹, Hiroki Nakagawa¹, Hiroki Ogawa¹, Fuyuki Nabeshima¹, Atsutaka Maeda¹

Affiliation

¹ Department of Basic Science, University of Tokyo, Meguro 153-8902, Tokyo, Japan.

PMID: 37402379
DOI: 10.1088/1361-648X/ace410

Abstract

In this study, we grow FeSe/SrTiO₃with thicknesses of 4-19 nm using pulsed laser deposition and investigate their magneto-transport properties. The thinnest film (4 nm) exhibit negative Hall effect, indicating electron transfer into FeSe from the SrTiO₃substrate. This is in agreement with reports on ultrathin FeSe/SrTiO₃grown by molecular beam epitaxy. The upper critical field is found to exhibit large anisotropy (γ>11.9), estimated from the data near the transition temperature (Tc). In particular, the estimated coherence lengths in the perpendicular direction are 0.15-0.27 nm, which are smaller than thec-axis length of FeSe, and are found to be almost independent of the total thicknesses of the films. These results indicate that superconductivity is confined at the interface of FeSe/SrTiO₃.

Keywords: PLD grown films; anisotropy of upper critical fields; interface superconductivity; iron-based superconductor.

MeSH terms

Anisotropy
Superconductivity*