Abstract
Time-dependent density-functional theory is a rather accurate and efficient way to compute electronic excitations for finite systems. However, in the macroscopic limit (systems of increasing size), for the usual adiabatic random-phase, local-density, or generalized-gradient approximations, one recovers the Kohn-Sham independent-particle picture, and thus the incorrect band gap. To clarify this trend, we investigate the macroscopic limit of the exchange-correlation kernel in such approximations by means of an algebraical analysis complemented with numerical studies of a one-dimensional tight-binding model. We link the failure to shift the Kohn-Sham spectrum of these approximate kernels to the fact that the corresponding operators in the transition space act only on a finite subspace.
Original language | English |
---|---|
Article number | 035126 |
Pages (from-to) | - |
Number of pages | 6 |
Journal | Physical Review B (Condensed Matter) |
Volume | 76 |
Issue number | 3 |
DOIs | |
Publication status | Published - Jul 2007 |