Negative resistance state in superconducting NbSe2 induced by surface acoustic waves

Masahiko Yokoi; Satoshi Fujiwara; Tomoya Kawamura; Tomonori Arakawa; Kazushi Aoyama; Hiroshi Fukuyama; Kensuke Kobayashi; Yasuhiro Niimi

doi:10.1126/sciadv.aba1377

Negative resistance state in superconducting NbSe₂ induced by surface acoustic waves

Sci Adv. 2020 Aug 21;6(34):eaba1377. doi: 10.1126/sciadv.aba1377. Print 2020 Aug.

Authors

Masahiko Yokoi¹, Satoshi Fujiwara¹, Tomoya Kawamura¹, Tomonori Arakawa^{1

2}, Kazushi Aoyama³, Hiroshi Fukuyama^{4

5}, Kensuke Kobayashi^{1

4

6}, Yasuhiro Niimi^{7

2}

Affiliations

¹ Department of Physics, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan.
² Center for Spin Research Network, Osaka University, Toyonaka 560-8531, Japan.
³ Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan.
⁴ Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan.
⁵ Cryogenic Research Center, The University of Tokyo, Tokyo 113-0032, Japan.
⁶ Institute for Physics of Intelligence, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan.
⁷ Department of Physics, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan. niimi@phys.sci.osaka-u.ac.jp.

Abstract

We report a negative resistance, namely, a voltage drop along the opposite direction of a current flow, in the superconducting gap of NbSe₂ thin films under the irradiation of surface acoustic waves (SAWs). The amplitude of the negative resistance becomes larger by increasing the SAW power and decreasing temperature. As one possible scenario, we propose that soliton-antisoliton pairs in the charge density wave of NbSe₂ modulated by the SAW serve as a time-dependent capacitance in the superconducting state, leading to the dc negative resistance. The present experimental result would provide a previously unexplored way to examine nonequilibrium manipulation of the superconductivity.

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