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Electronic evidence of an insulator–superconductor crossover in single-layer FeSe/SrTiO3 films

Journal Article


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Abstract


  • In high-temperature cuprate superconductors, it is now generally

    agreed that superconductivity is realized by doping an antiferromagnetic

    Mott (charge transfer) insulator. The doping-induced

    insulator-to-superconductor transition has been widely observed in

    cuprates, which provides important information for understanding

    the superconductivity mechanism. In the iron-based superconductors,

    however, the parent compound is mostly antiferromagnetic

    bad metal, raising a debate on whether an appropriate starting point

    should go with an itinerant picture or a localized picture. No

    evidence of doping-induced insulator–superconductor transition (or

    crossover) has been reported in the iron-based compounds so far.

    Here, we report an electronic evidence of an insulator–superconductor

    crossover observed in the single-layer FeSe film grown on a SrTiO3

    substrate. By taking angle-resolved photoemission measurements on

    the electronic structure and energy gap, we have identified a clear

    evolution of an insulator to a superconductor with increasing carrier

    concentration. In particular, the insulator–superconductor crossover

    in FeSe/SrTiO3 film exhibits similar behaviors to that observed in the

    cuprate superconductors. Our results suggest that the observed insulator–superconductor

    crossover may be associated with the twodimensionality

    that enhances electron localization or correlation. The

    reduced dimensionality and the interfacial effect provide a new

    pathway in searching for new phenomena and novel superconductors

    with a high transition temperature.

UOW Authors


  •   He, Junfeng (external author)
  •   Liu, Xu (external author)
  •   Zhang, Wenhao (external author)
  •   Zhao, Lin (external author)
  •   Liu, Defa (external author)
  •   He, Shaolong (external author)
  •   Mou, Daixiang (external author)
  •   Li, Fangsen (external author)
  •   Tang, Chenjia (external author)
  •   Li, Zhi
  •   Wang, Lili (external author)
  •   Peng, Yingying (external author)
  •   Liu, Yan (external author)
  •   Chen, Chaoyu (external author)
  •   Yu, Li (external author)
  •   Liu, Guodong (external author)
  •   Dong, Xiaoli (external author)
  •   Zhang, Jun (external author)
  •   Chen, Chuangtian (external author)
  •   Xu, Zuyan (external author)
  •   Chen, Xi (external author)
  •   Ma, Xu-Cun (external author)
  •   Xue, Qi-Kun (external author)
  •   Zhou, X J. (external author)

Publication Date


  • 2014

Geographic Focus


Citation


  • He, J., Liu, X., Zhang, W., Zhao, L., Liu, D., He, S., Mou, D., Li, F., Tang, C., Li, Z., Wang, L., Peng, Y., Liu, Y., Chen, C., Yu, L., Liu, G., Dong, X., Zhang, J., Chen, C., Xu, Z., Chen, X., Ma, X., Xue, Q. & Zhou, X. (2014). Electronic evidence of an insulator–superconductor crossover in single-layer FeSe/SrTiO3 films. Proceedings of the National Academy of Sciences of USA, 111 (52), 18501-18506.

Scopus Eid


  • 2-s2.0-84921045289

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=3628&context=aiimpapers

Ro Metadata Url


  • http://ro.uow.edu.au/aiimpapers/2583

Number Of Pages


  • 5

Start Page


  • 18501

End Page


  • 18506

Volume


  • 111

Issue


  • 52

Place Of Publication


  • United States

Abstract


  • In high-temperature cuprate superconductors, it is now generally

    agreed that superconductivity is realized by doping an antiferromagnetic

    Mott (charge transfer) insulator. The doping-induced

    insulator-to-superconductor transition has been widely observed in

    cuprates, which provides important information for understanding

    the superconductivity mechanism. In the iron-based superconductors,

    however, the parent compound is mostly antiferromagnetic

    bad metal, raising a debate on whether an appropriate starting point

    should go with an itinerant picture or a localized picture. No

    evidence of doping-induced insulator–superconductor transition (or

    crossover) has been reported in the iron-based compounds so far.

    Here, we report an electronic evidence of an insulator–superconductor

    crossover observed in the single-layer FeSe film grown on a SrTiO3

    substrate. By taking angle-resolved photoemission measurements on

    the electronic structure and energy gap, we have identified a clear

    evolution of an insulator to a superconductor with increasing carrier

    concentration. In particular, the insulator–superconductor crossover

    in FeSe/SrTiO3 film exhibits similar behaviors to that observed in the

    cuprate superconductors. Our results suggest that the observed insulator–superconductor

    crossover may be associated with the twodimensionality

    that enhances electron localization or correlation. The

    reduced dimensionality and the interfacial effect provide a new

    pathway in searching for new phenomena and novel superconductors

    with a high transition temperature.

UOW Authors


  •   He, Junfeng (external author)
  •   Liu, Xu (external author)
  •   Zhang, Wenhao (external author)
  •   Zhao, Lin (external author)
  •   Liu, Defa (external author)
  •   He, Shaolong (external author)
  •   Mou, Daixiang (external author)
  •   Li, Fangsen (external author)
  •   Tang, Chenjia (external author)
  •   Li, Zhi
  •   Wang, Lili (external author)
  •   Peng, Yingying (external author)
  •   Liu, Yan (external author)
  •   Chen, Chaoyu (external author)
  •   Yu, Li (external author)
  •   Liu, Guodong (external author)
  •   Dong, Xiaoli (external author)
  •   Zhang, Jun (external author)
  •   Chen, Chuangtian (external author)
  •   Xu, Zuyan (external author)
  •   Chen, Xi (external author)
  •   Ma, Xu-Cun (external author)
  •   Xue, Qi-Kun (external author)
  •   Zhou, X J. (external author)

Publication Date


  • 2014

Geographic Focus


Citation


  • He, J., Liu, X., Zhang, W., Zhao, L., Liu, D., He, S., Mou, D., Li, F., Tang, C., Li, Z., Wang, L., Peng, Y., Liu, Y., Chen, C., Yu, L., Liu, G., Dong, X., Zhang, J., Chen, C., Xu, Z., Chen, X., Ma, X., Xue, Q. & Zhou, X. (2014). Electronic evidence of an insulator–superconductor crossover in single-layer FeSe/SrTiO3 films. Proceedings of the National Academy of Sciences of USA, 111 (52), 18501-18506.

Scopus Eid


  • 2-s2.0-84921045289

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=3628&context=aiimpapers

Ro Metadata Url


  • http://ro.uow.edu.au/aiimpapers/2583

Number Of Pages


  • 5

Start Page


  • 18501

End Page


  • 18506

Volume


  • 111

Issue


  • 52

Place Of Publication


  • United States