1 research outputs found
Pressure-Induced Changes on The Electronic Structure and Electron Topology in the Direct FCC → SH Transformation of Silicon
X-ray diffraction experiments at 80 K show that when silicon is
compressed under hydrostatic conditions the intermediate high-pressure
phases are bypassed leading to a direct transformation to the simple
hexagonal structure at 17 GPa. A maximum entropy analysis of the diffraction
patterns reveals dramatic alterations in the valence electron distribution
from tetrahedral covalent bonding to localization in the interstitial
sites and along the one-dimensional silicon atom chain running along
adjacent hexagonal layers. Changes in the orbital character of the
unoccupied states are confirmed using X-ray Raman scattering spectroscopy
and theoretical Bethe-Salpeter equation calculations. This is the
first direct observation indicating that the silicon valence electrons
in 3s and 3p orbitals are transferred to the 3d orbitals at high density
which proves that electrons of compressed elemental solids migrate
from their native bonding configuration to interstitial regions