中国物理B ›› 2023, Vol. 32 ›› Issue (5): 57303-057303.doi: 10.1088/1674-1056/ac9b30

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Hydrogenic donor impurity states and intersubband optical absorption spectra of monolayer transition metal dichalcogenides in dielectric environments

Shu-Dong Wu(吴曙东)   

  1. College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China
  • 收稿日期:2022-06-05 修回日期:2022-10-08 接受日期:2022-10-19 出版日期:2023-04-21 发布日期:2023-04-26
  • 通讯作者: Shu-Dong Wu E-mail:sdwu@yzu.edu.cn

Hydrogenic donor impurity states and intersubband optical absorption spectra of monolayer transition metal dichalcogenides in dielectric environments

Shu-Dong Wu(吴曙东)   

  1. College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China
  • Received:2022-06-05 Revised:2022-10-08 Accepted:2022-10-19 Online:2023-04-21 Published:2023-04-26
  • Contact: Shu-Dong Wu E-mail:sdwu@yzu.edu.cn

摘要: The hydrogenic donor impurity states and intersubband optical absorption spectra in monolayer transition metal dichalcogenides (ML TMDs) under dielectric environments are theoretically investigated based on a two-dimensional (2D) nonorthogonal associated Laguerre basis set. The 2D quantum confinement effect together with the strongly reduced dielectric screening results in the strong attractive Coulomb potential between electron and donor ion, with exceptionally large impurity binding energy and huge intersubband oscillator strength. These lead to the strong interaction of the electron with light in a 2D regime. The intersubband optical absorption spectra exhibit strong absorption lines of the non-hydrogenic Rydberg series in the mid-infrared range of light. The strength of the Coulomb potential can be controlled by changing the dielectric environment. The electron affinity difference leads to charge transfer between ML TMD and the dielectric environment, generating the polarization-electric field in ML TMD accompanied by weakening the Coulomb interaction strength. The larger the dielectric constant of the dielectric environment, the more the charge transfer is, accompanied by the larger polarization-electric field and the stronger dielectric screening. The dielectric environment is shown to provide an efficient tool to tune the wavelength and output of the mid-infrared intersubband devices based on ML TMDs.

关键词: monolayer transition metal dichalcogenides, hydrogenic donor impurity, intersubband optical absorption, dielectric environment, nonorthogonal associated Laguerre basis

Abstract: The hydrogenic donor impurity states and intersubband optical absorption spectra in monolayer transition metal dichalcogenides (ML TMDs) under dielectric environments are theoretically investigated based on a two-dimensional (2D) nonorthogonal associated Laguerre basis set. The 2D quantum confinement effect together with the strongly reduced dielectric screening results in the strong attractive Coulomb potential between electron and donor ion, with exceptionally large impurity binding energy and huge intersubband oscillator strength. These lead to the strong interaction of the electron with light in a 2D regime. The intersubband optical absorption spectra exhibit strong absorption lines of the non-hydrogenic Rydberg series in the mid-infrared range of light. The strength of the Coulomb potential can be controlled by changing the dielectric environment. The electron affinity difference leads to charge transfer between ML TMD and the dielectric environment, generating the polarization-electric field in ML TMD accompanied by weakening the Coulomb interaction strength. The larger the dielectric constant of the dielectric environment, the more the charge transfer is, accompanied by the larger polarization-electric field and the stronger dielectric screening. The dielectric environment is shown to provide an efficient tool to tune the wavelength and output of the mid-infrared intersubband devices based on ML TMDs.

Key words: monolayer transition metal dichalcogenides, hydrogenic donor impurity, intersubband optical absorption, dielectric environment, nonorthogonal associated Laguerre basis

中图分类号:  (Surface double layers, Schottky barriers, and work functions)

  • 73.30.+y
71.55.-i (Impurity and defect levels) 71.35.Cc (Intrinsic properties of excitons; optical absorption spectra) 77.22.Ch (Permittivity (dielectric function))