TY - JOUR
T1 - Vortex-induced quantum metallicity in the mono-unit-layer superconductor NbS e2
AU - Ichinokura, Satoru
AU - Nakata, Yuki
AU - Sugawara, Katsuaki
AU - Endo, Yukihiro
AU - Takayama, Akari
AU - Takahashi, Takashi
AU - Hasegawa, Shuji
N1 - Funding Information:
We thank R. Akiyama and R. Hobara at The University of Tokyo, and T. Sato at Tohoku University for their useful discussions. This work was supported by the JSPS (KAKENHI JP15J11055, JP25246025, JP15H02105, JP18H01821, JP18H01160, JP18J10038) and the MEXT (Grant-in-Aid for Scientific Research on Innovative Areas “Science of Atomic Layers” JP25107003 and “Molecular Architectonics” JP25110010), and the Program for Key Interdisciplinary Research. Also acknowledged is a grant for Basic Science Research Projects from the Sumitomo Foundation, Science Research Projects from Iketani Science and Technology Foundation, the Program for Key Interdisciplinary Research, and World Premier International Research Center, Advanced Institute for Materials Research.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/6/5
Y1 - 2019/6/5
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevB.99.220501
DO - 10.1103/PhysRevB.99.220501
M3 - Article
AN - SCOPUS:85067194660
VL - 99
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 2469-9950
IS - 22
M1 - 220501
ER -