Surface correlation effects in two-band strongly correlated slabs

Abstract

Using an extension of the Gutzwiller approximation for an inhomogeneous system, we study the two-band Hubbard model with unequal band widths for a slab geometry. The aim is to investigate the mutual effect of individual bands on the spatial distribution of quasi-particle weight and charge density, especially near the surface of the slab. The main effect of the difference in band width is the presence of two different length scales corresponding to the quasi-particle profile of each band. This is enhanced in the vicinity of the critical interaction of the narrow band where an orbitally selective Mott transition occurs and a surface dead layer forms for the narrow band. For the doped case, two different regimes of charge transfer between the surface and the bulk of the slab are revealed. The charge transfer from surface/center to center/surface depends on both the doping level and the average relative charge accumulated in each band. Such effects could also be of importance when describing the accumulation of charges at the interface between structures made of multi-band strongly correlated materials.

Electric-field-driven Mott metal-insulator transition in correlated thin films: An inhomogeneous dynamical mean-field theory approach

“…13 This has stimulated the development of alternative methods. The Gutzwiller approximation [14][15][16] and slave boson techniques 17,18 have been used to treat the low-energy physics of bulk materials and -more recently -thin films [19][20][21][22][23][24] in the presence of an electric field. 21,22 The slave boson approach has been extended to allow access to higher-energy excitations 25 , while the Gutzwiller approximation only provides insight into the metallic state.…”