Absence of metallicity in Cs-GaAs(110): A Hubbard-model study

Using an approximate solution of the Hubbard-model Hamiltonian, we are able to establish that the Cs-GaAs(110) system becomes a Mott insulator at submonolayer Cs coverages. We also provide a consistent interpretation of electron-energy-loss and scanning-tunneling-spectroscopies data. The correlation effects are important for this system with an estimated correlation energy of 0.4 eV. © 1993 The American Physical Society.