Variational Monte Carlo in solids

Physical and computational issues related to correlated Jastrow-Slater wavefunctions for the electrons in solids are discussed. The physics of short- and long-range correlation terms in the Jastrow factor is reviewed. The representation and evaluation of single-particle orbitals is also discussed. Pseudopotentials are used to give a separation of valence and core electron degrees of freedom so that QMC methods can then be used to treat the correlation of valence electrons only. Methods for the evaluation of non-local, angular-momentum-dependent pseudopotentials, along with general methods for the evaluation of local potentials in periodically extended systems are presented. The use of modified boundary conditions and electron-electron interactions for the reduction of finite-size effects is briefly discussed. Applications of these methods to the calculation of cohesive energies, correlation functions, and Compton profiles for solids are reviewed.