Unconventional superconductivity in the single-atom-layer alloy Si(111)-√3×√3-(Tl, Pb)

T. Nakamura, H. Kim, S. Ichinokura, A. Takayama, A. V. Zotov, A. A. Saranin, Y. Hasegawa, S. Hasegawa

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13 Citations (Scopus)


We present results of low-temperature scanning tunneling microscopy/spectroscopy measurements on the one-atom-layer superconductor, Si(111)-√3×√3-(Tl,Pb) which has a spin-split band structure due to the Rashba-Bychkov effect. It was revealed that it has a multiple superconducting gap Δ with significant anisotropy and sizable magnitude of 2Δ/kBTC∼8.6(kB is the Boltzmann constant and TC is the critical superconducting temperature). Under the magnetic field, a dip structure was observed even at the core of the vortex. The dip structure was like a "pseudogap" because it remained up to 2 T, well above the upper critical magnetic field determined in the transport measurements (∼0.7 T). This unconventional behavior suggests the possibility of spin-triplet Cooper pairs related to parity-broken superconductors.

Original languageEnglish
Article number134505
JournalPhysical Review B
Issue number13
Publication statusPublished - 2018 Oct 16
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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