Real-Space Analysis of the Optical Absorption in Alternative Phases of Silicon

ORAL

Abstract

We introduce a real-space approach to understand the relationship between optical absorption and crystal structure. This approach is applied to some alternative phases of silicon in addition to the diamond structure, with a focus on the Si$_{20}$ crystal phase as a case study. We find that about 83{\%} of the enhancement in the calculated low-energy absorption in Si$_{20}$ can be attributed to reducing the differences between the on-site energies of the bonding and anti-bonding orbitals as well as to increasing the magnitude of the hopping integrals for specific Si-Si bonds. This work was supported by NSF grant No. DMR-1508412 and the DOE under Contract No. DE-AC02-05CH11231. Computational resources have been provided by DOE at Lawrence Berkeley National Laboratory's NERSC facility.

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Authors

  • Chin Shen Ong

    Department of Physics, UC Berkeley and Lawrence Berkeley National Lab

  • Sinisa Coh

    Mechanical Engineering, Materials Science and Engineering, UC Riverside, UC Riverside

  • Marvin L. Cohen

    Department of Physics, UC Berkeley and Lawrence Berkeley National Lab

  • Steven G. Louie

    Department of Physics, UC Berkeley and Lawrence Berkeley National Lab, UC Berkeley and Lawrence Berkeley National Lab, University of California at Berkeley and Lawrence Berkeley National Lab, Physics Department, UC Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Univ of California - Berkeley and Lawrence Berkeley National Lab