Berezinskii-Kosterlitz-Thouless transition in an Al superconducting nanofilm grown on GaAs by molecular beam epitaxy

Guan Ming Su, Bi Yi Wu, Yen Ting Fan, Ankit Kumar, Chau Shing Chang, Ching Chen Yeh, Dinesh K. Patel, Sheng Di Lin*, Lee Chow, Chi Te Liang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We have performed extensive transport experiments on a 4 nm thick aluminum (Al) superconducting film grown on a GaAs substrate by molecular beam epitaxy (MBE). Nonlinear current-voltage (I-V) measurements on such a MBE-grown superconducting nanofilm show that V ∼ I 3, which is evidence for the Berezinskii-Kosterlitz-Thouless (BKT) transition, both in the low-voltage (T BKT ≈ 1.97 K) and high-voltage regions (T BKT ≈ 2.17 K). In order to further study the two regions where the I-V curves are BKT-like, our experimental data are fitted to the temperature-induced vortices/antivortices unbinding model as well as the dynamical scaling theory. It is found that the transition temperature obtained in the high-voltage region is the correct T BKT as confirmed by fitting the data to the aforementioned models. Our experimental results unequivocally show that I-V measurements alone may not allow one to determine T BKT for superconducting transition. Therefore, one should try to fit one's results to the temperature-induced vortices/antivortices unbinding model and the dynamical scaling theory to accurately determine T BKT in a two-dimensional superconductor.

Original languageEnglish
Article number205002
JournalNanotechnology
Volume31
Issue number20
DOIs
StatePublished - 15 May 2020

Keywords

  • aluminum
  • GaAs substrate
  • nanofilm
  • superconductivity
  • two-dimensional

Fingerprint Dive into the research topics of 'Berezinskii-Kosterlitz-Thouless transition in an Al superconducting nanofilm grown on GaAs by molecular beam epitaxy'. Together they form a unique fingerprint.

Cite this