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Session Q12 - DCMP: DENSITY FUNCTIONAL THEORY
Mixed session, Friday morning, March 24, 8:00
Room C1, San Jose Convention Center
It is well known that the Local Density Approximation (LDA) has encountered difficulties in predicting some electronic properties of solids due to the approximate nature of the exchange-correlation interaction. In order to overcome the limitations of the LDA, we study the role of electron correlations in Si in a pseudopotential Variational Monte Carlo approach. Our trial wavefunction uses LDA single-particle orbitals modified by a correlation factor. Several models of electron correlation are compared, including a form based on the local approach of Fulde, Solids, (Berlin, Springer-Verlag), 1991. which incorporates the effects of the inhomogeneous environment in a physically intuitive way. We present results for the ground-state of Si, and discuss efforts to calculate low-lying excited states.