Research Article

Nano Research

, Volume 3, Issue 11, pp 800-806

Open Access This content is freely available online to anyone, anywhere at any time.

Van Hove singularities as a result of quantum confinement: The origin of intriguing physical properties in Pb thin films

  • Yu Jie SunAffiliated withKey Laboratory of Atomic and Nanosciences, Department of Physics, Tsinghua UniversityWPI Advanced Institute for Materials Research, Tohoku University
  • , S. SoumaAffiliated withWPI Advanced Institute for Materials Research, Tohoku University
  • , Wen Juan LiAffiliated withInstitute of Physics, The Chinese Academy of Sciences
  • , T. SatoAffiliated withDepartment of Physics, Tohoku University
  • , Xie Gang ZhuAffiliated withKey Laboratory of Atomic and Nanosciences, Department of Physics, Tsinghua University
  • , Guang WangAffiliated withKey Laboratory of Atomic and Nanosciences, Department of Physics, Tsinghua University
  • , Xi ChenAffiliated withKey Laboratory of Atomic and Nanosciences, Department of Physics, Tsinghua University
  • , Xu Cun MaAffiliated withInstitute of Physics, The Chinese Academy of Sciences
  • , Qi Kun XueAffiliated withKey Laboratory of Atomic and Nanosciences, Department of Physics, Tsinghua UniversityWPI Advanced Institute for Materials Research, Tohoku UniversityInstitute of Physics, The Chinese Academy of Sciences
    • , Jin Feng JiaAffiliated withKey Laboratory of Atomic and Nanosciences, Department of Physics, Tsinghua University Email author 
    • , T. TakahashiAffiliated withWPI Advanced Institute for Materials Research, Tohoku UniversityDepartment of Physics, Tohoku University
    • , T. SakuraiAffiliated withWPI Advanced Institute for Materials Research, Tohoku University

Abstract

In situ angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy (STS) have been used to study the electronic structure of Pb thin films grown on a Si(111) substrates. The experiments reveal that the electronic structure near the Fermi energy is dominated by a set of m-shaped subbands because of strong quantum confinement in the films, and the tops of the m-shaped subbands form an intriguing ring-like Van Hove singularity. Combined with theoretical calculations, we show that it is the Van Hove singularity that leads to an extremely high density of states near the Fermi energy and the recently reported strong oscillations (with a period of two monolayers) in various properties of Pb films.

Keywords

Van Hove singularity angle-resolved photoemission spectroscopy (ARPES) scanning tunneling spectroscopy (STS) Pb film