Doubling the superconducting transition temperature of ultraclean wafer-scale aluminum nanofilms

Ching Chen Yeh, Thi Hien Do, Pin Chi Liao, Chia Hung Hsu, Yi Hsin Tu, Hsin Lin, T. R. Chang, Siang Chi Wang, Yu Yao Gao, Yu Hsun Wu, Chu Chun Wu, Yu An Lai, Ivar Martin, Sheng Di Lin, Christos Panagopoulos, Chi Te Liang

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

We studied the role of reduced dimensionality and disorder in the superconducting properties of wafer-scale aluminum (Al) nanofilms. This new generation of ultrathin films were grown using molecular beam epitaxy and depict normal-state sheet resistance at least 20 times lower than the quantum resistance h/(4e2). Defying general expectations, the superconducting transition temperature of our films increases with decreasing Al film thickness, reaching 2.4 K for a 3.5-nm-thick Al film grown on GaAs: twice that of bulk Al (1.2 K). Surface phonon softening is shown to impact superconductivity in pure ultrathin films, offering a route for materials engineering in two dimensions.

Original languageEnglish
Article number114801
JournalPhysical Review Materials
Volume7
Issue number11
DOIs
Publication statusPublished - 2023 Nov

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Physics and Astronomy (miscellaneous)

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