Mapping the electron correlation onto a model Hamiltonian for Cs/GaAs(110): A Mott-Hubbard insulator at quarter filling Article

Chen, C, Wang, XW. (1998). Mapping the electron correlation onto a model Hamiltonian for Cs/GaAs(110): A Mott-Hubbard insulator at quarter filling . JOURNAL OF PHYSICS-CONDENSED MATTER, 10(4), 731-739. 10.1088/0953-8984/10/4/003

cited authors

  • Chen, C; Wang, XW

authors

abstract

  • We have constructed an effective model Hamiltonian in the Hubbard formalism for the Cs/GaAs(110) surface at quarter-monolayer coverage with all of the parameters extracted from constrained local-density-approximation (LDA) pseudopotential calculations. The single-particle excitation spectrum of the model has been calculated using an exact-diagonalization technique to help determine the relevant interaction terms. It is shown that the intersite interaction between the nearest-neighbour Ga sites plays the key role in determining the insulating nature of the system and must be included in the model, in contrast to suggestions of some previous work. Our results show that a reliable mapping of LDA results onto an effective model Hamiltonian can be achieved by combining constrained LDA calculations for the Hamiltonian parameters and many-body calculations of the single-particle excitation spectrum for identifying relevant interaction terms.

publication date

  • February 2, 1998

published in

Digital Object Identifier (DOI)

start page

  • 731

end page

  • 739

volume

  • 10

issue

  • 4