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Charge Density Waves and Superconductivity at the Single-layer Limit in NbSe2

Charge Density Waves and Superconductivity at the Single-layer Limit in NbSe<sub>2</sub>IMAGE LEGEND.

Scientific Achievement
First atomic-scale study of single-layer NbSe2. The coexistence of charge density wave (CDW) order and superconductivity have been confirmed at the single-layer limit for a 2D transition metal dichalcogenide material.

Significance and Impact
The manybody ground state of NbSe2 has been clarified, allowing quantitative exploration of the interplay between collective phenomena in reduced dimensions.

Research Details

  • The electronic CDW pattern in single-layer NbSe2 was imaged by atomically-resolved scanning tunneling microscopy.
  • The simplified band structure of single-layer NbSe2 was determined using angle-resolved photoemission (ARPES ) and scanning tunneling spectroscopy (STS), enabling different theories for the ground state of NbSe2 to be ruled out.
  • Superconductivity in single-layer NbSe2 was found at 1.9 K via transport measurement, revealing NbSe2 to be one of the few 2D materials that can exhibit superconductivity in isolation.

M Ugeda, A Bradley, Y Zhang, S Onishi, Y Chen, W Ruan, C Ojeda-Aristizabal, H Ryu, M Edmonds, H-Z Tsai, A Riss, S-K Mo, D-H Lee, A Zettl, Z Hussain, Z-X Shen, MF Crommie. Nature Physics (2015). DOI: 10.1038/NPHYS3527