Vortex-induced quantum metallicity in the mono-unit-layer superconductor NbS e2

Satoru Ichinokura, Yuki Nakata, Katsuaki Sugawara, Yukihiro Endo, Akari Takayama, Takashi Takahashi, Shuji Hasegawa

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


We performed in situ magnetoresistance measurements in the ultrahigh-vacuum environment to reveal the quantum phase transitions of single unit-layer NbSe2 epitaxially grown on bilayer graphene. It was found that the superconductor-normal state transition caused by the surface-normal magnetic field was intermediated by a quasimetallic state. This behavior is consistent with the "Bose metal" picture where a finite dissipation is caused by the breaking of phase coherence due to strong gauge-field fluctuation. On one hand, around the mean-field critical temperature, the onset of transition from the normal state to the low-temperature states was governed by the amplitude-fluctuation effect, prominently under the magnetic field. We applied scaling theories to determine the phase boundaries. The result of scaling analyses revealed a complex but essential phase diagram of the single unit-layer NbSe2 as a two-dimensional superconductor.

Original languageEnglish
Article number220501
JournalPhysical Review B
Issue number22
Publication statusPublished - 2019 Jun 5
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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