TY - JOUR
KW - paper
AU - Silvana Botti
AU - Francesco Sottile
AU - N Vast
AU - Olevano V
AU - Lucia Reining
AU - Hans-Christian Weissker
AU - Angel Rubio
AU - G Onida
AU - Rodolfo Del Sole
AU - RW Godby
AB - We discuss the effects of a static long-range contribution -alpha/q(2) to the exchange-correlation kernel f(xc)(q) of time-dependent density functional theory. We show that the optical absorption spectrum of solids exhibiting a strong continuum excitonic effect is considerably improved with respect to calculations where the adiabatic local-density approximation is used. We discuss the limitations of this simple approach, and in particular that the same improvement cannot be found for the whole spectral range including the valence plasmons and bound excitons. On the other hand, we also show that within the range of validity of the method, the parameter alpha depends linearly on the inverse of the dielectric constant, and we demonstrate that this fact can be used to predict continuum excitonic effects in semiconductors. Results are shown for the real and imaginary part of the dielectric function of Si, GaAs, AlAs, diamond, MgO, SiC and Ge, and for the loss function of Si.
BT - Phys. Rev. B
CY - ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
DA - APR
DO - 10.1103/PhysRevB.69.155112
M1 - 15
N2 - We discuss the effects of a static long-range contribution -alpha/q(2) to the exchange-correlation kernel f(xc)(q) of time-dependent density functional theory. We show that the optical absorption spectrum of solids exhibiting a strong continuum excitonic effect is considerably improved with respect to calculations where the adiabatic local-density approximation is used. We discuss the limitations of this simple approach, and in particular that the same improvement cannot be found for the whole spectral range including the valence plasmons and bound excitons. On the other hand, we also show that within the range of validity of the method, the parameter alpha depends linearly on the inverse of the dielectric constant, and we demonstrate that this fact can be used to predict continuum excitonic effects in semiconductors. Results are shown for the real and imaginary part of the dielectric function of Si, GaAs, AlAs, diamond, MgO, SiC and Ge, and for the loss function of Si.
PB - AMERICAN PHYSICAL SOC
PP - ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
PY - 2004
T2 - Phys. Rev. B
TI - Long-range contribution to the exchange-correlation kernel of time-dependent density functional theory
UR - http://dx.doi.org/10.1103/PhysRevB.69.155112
VL - 69
ER -