Mu Chen

Publications (6)17.29 Total impact

• Article: Mass acquisition of Dirac fermions in Cr-doped topological insulator Sb2Te3 films

  Yeping Jiang, Zhi Li, Canli Song, Mu Chen, Richard L. Greene, Ke He, Lili Wang, Xi Chen, Xucun Ma, Qi-Kun Xue
  [show abstract] [hide abstract]
  ABSTRACT: We introduce time-reversal-symmetry breaking by doping Cr atoms into the topmost quintuple layer or into the bulk of Sb2Te3 thin films. We find that even at a high Cr-doping level the Landau level spectrum keeps a good quality, enabling the first demonstration of deviation of the zero-mode Landau level, induced by the acquisition of a mass term in the surface states in the presence of surface or bulk magnetic doping. The magnitude of the mass term in the surface states increases with increasing Cr-doping level. Our observation suggests Cr-doped Sb2Te3 is a promising candidate for the realization of the proposed novel magnetoelectric effects.
  05/2013;
• Article: Scanning tunneling microscopy of interface properties of Bi(2)Se(3) on FeSe.

  Yilin Wang, Yeping Jiang, Mu Chen, Zhi Li, Canli Song, Lili Wang, Ke He, Xi Chen, Xucun Ma, Qi-Kun Xue
  [show abstract] [hide abstract]
  ABSTRACT: We investigate the heteroepitaxial growth of Bi(2)Se(3) films on FeSe substrates by low-temperature scanning tunneling microscopy/spectroscopy. The growth of Bi(2)Se(3) on FeSe proceeds via van der Waals epitaxy with atomically flat morphology. A striped moiré pattern originating from the lattice mismatch between Bi(2)Se(3) and FeSe is observed. Tunneling spectra reveal the spatially inhomogeneous electronic structure of the Bi(2)Se(3) thin films, which can be ascribed to the charge transfer at the interface.
  Journal of Physics Condensed Matter 10/2012; 24(47):475604. · 2.55 Impact Factor
• Article: Fermi-level tuning of epitaxial Sb2Te3 thin films on graphene by regulating intrinsic defects and substrate transfer doping.

  Yeping Jiang, Y Y Sun, Mu Chen, Yilin Wang, Zhi Li, Canli Song, Ke He, Lili Wang, Xi Chen, Qi-Kun Xue, Xucun Ma, S B Zhang
  [show abstract] [hide abstract]
  ABSTRACT: High-quality Sb2Te3 films are obtained by molecular beam epitaxy on a graphene substrate and investigated by in situ scanning tunneling microscopy and spectroscopy. Intrinsic defects responsible for the natural p-type conductivity of Sb2Te3 are identified to be the Sb vacancies and Sb(Te) antisites in agreement with first-principles calculations. By minimizing defect densities, coupled with a transfer doping by the graphene substrate, the Fermi level of Sb2Te3 thin films can be tuned over the entire range of the bulk band gap. This establishes the necessary condition to explore topological insulator behaviors near the Dirac point.
  Physical Review Letters 02/2012; 108(6):066809. · 7.37 Impact Factor
• Article: Landau quantization and the thickness limit of topological insulator thin films of Sb2Te3.

  Yeping Jiang, Yilin Wang, Mu Chen, Zhi Li, Canli Song, Ke He, Lili Wang, Xi Chen, Xucun Ma, Qi-Kun Xue
  [show abstract] [hide abstract]
  ABSTRACT: We report the experimental observation of Landau quantization of molecular beam epitaxy grown Sb{2}Te{3} thin films by a low-temperature scanning tunneling microscope. Different from all the reported systems, the Landau quantization in a Sb{2}Te{3} topological insulator is not sensitive to the intrinsic substitutional defects in the films. As a result, a nearly perfect linear energy dispersion of surface states as a 2D massless Dirac fermion system is achieved. We demonstrate that four quintuple layers are the thickness limit for a Sb{2}Te{3} thin film being a 3D topological insulator. The mechanism of the Landau-level broadening is discussed in terms of enhanced quasiparticle lifetime.
  Physical Review Letters 01/2012; 108(1):016401. · 7.37 Impact Factor
• Article: Phases and phase transitions in two dimensional superconducting films

  Weiwei Zhao, Qingyan Wang, Minhao Liu, Wenhao Zhang, Yilin Wang, Mu Chen, Yang Guo, Ke He, Xi Chen, Yayu Wang, Jian Wang, Xincheng Xie, Qian Niu, Lili Wang, Xucun Ma, Jainendra Jain, M. H. W. Chan, Qi-Kun Xue
  [show abstract] [hide abstract]
  ABSTRACT: This paper has been withdrawn by the author
  12/2011;
• Article: Structural defects and electronic properties of the Cu-doped topological insulator Bi_ {2} Se_ {3}

  Yi-Lin Wang, Yong Xu, Ye-Ping Jiang, Jun-Wei Liu, Cui-Zu Chang, Mu Chen, Zhi Li, Can-Li Song, Li-Li Wang, Ke He, Xi Chen, Wen-Hui Duan, Qi-Kun Xue, Xu-Cun Ma
  [show abstract] [hide abstract]
  ABSTRACT: Motivated by the occurrence of superconductivity transition in Cu-doped topological insulator Bi2Se3, we perform a combined study of low temperature scanning tunneling microscopy/spectroscopy and angle-resolved photoemission spectroscopy experiments and of ab initio density functional theory to clarify the doping nature of Cu atoms in Bi2Se3 films. By measuring the structural and electronic properties of the Cu-doped Bi2Se3 films at different doping temperatures, we find that Cu atoms behave as donors at intercalated and interstitial sites in Bi2Se3 films. Only the interstitial defect density plays an important role in the observation of Landau quantization of the topological surface states in Bi2Se3.
  Phys. Rev. B. 84(7).