Lawrence Livermore National Laboratory

Nanoscale physics has emerged as an important new research area with many potential technology applications. With support from a Basic Energy Sciences (BES) program, entitled "Growth and Formation of Advanced Heterointerfaces," we are carrying out a number of joint theoretical and experimental studies. The mandate for the program is to integrate state-of-the-art theoretical and experimental surface and interface physics activities. Recent projects include joint studies of the electronic structure of Pt-silicides, the structure and stability of Ge nanoparticles, band mapping in hexagonal MoS2, the orbital-resolved electronic structure of CdSe nanoparticles, and the optical properties of hydrogen-terminated Si nanoparticles, among others. We are also exploring new methods for efficiently calculating the x-ray absorption spectra (XAS) of nanoparticles using the FP-LMTO method. A collaboration exists with Oleg Pankratov at the University of Erlangen-Nuremberg  in Germany.

Selected Publications

  1. L. X. Benedict, A. Puzder, A. J. Williamson, J. C. Grossman, G. Galli, J. E. Klepeis, J.-Y. Raty, and O. Pankratov, "Calculation of optical absorption spectra of hydrogenated Si clusters: Bethe-Salpeter equation versus time-dependent local-density approximation ," Phys. Rev. B 68, 085310 (2003).
  2. N. Franco, J. E. Klepeis, C. Bostedt, T. Van Buuren, C. Heske, O. Pankratov, T. A. Callcott, D. L. Ederer, and L. J. Terminello, "Experimental and theoretical electronic structure determination for PtSi ," Phys. Rev. B 68, 045116 (2003).
  3. L. X. Benedict, "Screening in the exchange term of the electron-hole interaction of the Bethe-Salpeter equation ," Phys. Rev. B 66, 193105 (2002).
  4. L. Pizzagalli, G. Galli, J. E. Klepeis, and F. Gygi, "Structure and stability of germanium nanoparticles ," Phys. Rev. B 63, 165324 (2001).
  5. J. E. Klepeis, O. Beckstein, O. Pankratov, and G. L. W. Hart, "Chemical bonding, elasticity, and valence force field models: A case study for alpha-Pt2Si and PtSi ," Phys. Rev. B 64, 155110 (2001).
  6. L. X. Benedict and E. L. Shirley, "Ab initio calculation of epsilon2(omega) including the electron-hole interaction: Application to GaN and CaF2 ," Phys. Rev. B 59, 5441 (1999).
FP-LMTO calculation of the Fermi surface for tetragonal alpha-Pt2Si.

FP-LMTO calculation of the Fermi surface for tetragonal alpha-Pt2Si. Metallic Pt silicide compounds such as alpha-Pt2Si are used to make rectifying junctions on silicon substrates. The Fermi surface in the figure exhibits a significant degree of anisotropy, with large and relatively flat sheets oriented along one particular direction. The form of the Fermi surface is directly connected to the nature of the tunneling that occurs at the Pt silicide/Si(001) interface.

Maintained by   Randolph Q. Hood