Dielectric properties of multiband electron systems: I - Tight-binding formulation

Details Dielectric properties of multiband electron systems: I - Tight-binding formulation Dielectric properties of multiband electron systems: I - Tight-binding formulation

1996-02-28

arxiv.org/abs/cond-mat/9602151v1

Physics

Condensed Matter

32 pages, LaTeX, to appear in Z.Phys. B

Scientific paper

10.1007/s002570050224

The screened electron-electron interaction in a multi-band electron system is calculated within the random phase approximation and in the tight-binding representation. The obtained dielectric matrix contains, beside the usual site-site correlations, also the site-bond and bond-bond correlations, and thus includes all physically relevant polarization processes. The arguments are given that the bond contributions are negligible in the long wavelength limit. We analyse the system with two non-overlapping bands in this limit, and show that the corresponding dielectric matrix reduces to a $2\times2$ form. The intra-band and inter-band contributions are represented by diagonal matrix elements, while the off-diagonal elements contain the mixing between them. The latter is absent in insulators but may be finite in conductors. Performing the multipole expansion of the bare long-range interaction, we show that this mixing is directly related to the symmetry of the atomic orbitals participating in the tight-binding electronic states. In systems with forbidden atomic dipolar transitions, the intra-band and inter-band polarizations are separated. However, when the dipolar transitions are allowed, the off-diagonal elements of the dielectric matrix are of the same order as diagonal ones, due to a finite monopole-dipole interaction between the intra-band and inter-band charge fluctuations.

Affiliated with

Also associated with

No associations

Rating

Dielectric properties of multiband electron systems: I - Tight-binding formulation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Dielectric properties of multiband electron systems: I - Tight-binding formulation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dielectric properties of multiband electron systems: I - Tight-binding formulation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-460302