Surface correlation effects in two-band strongly correlated slabs

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• The Hubbard model is crucial for understanding strongly correlated electron systems.
• Inhomogeneous systems and multi-band materials present unique electronic behaviors, especially near surfaces and interfaces.

Purpose of the Study:

• To investigate the spatial distribution of quasi-particle weight and charge density in a two-band Hubbard model with unequal band widths.
• To explore the impact of band width differences on surface phenomena like Mott transitions and dead layers.
• To analyze charge transfer dynamics between the surface and bulk in doped inhomogeneous systems.

Main Methods:

• Utilizing an extension of the Gutzwiller approximation for inhomogeneous systems.
• Applying the model to a slab geometry to study surface and bulk effects.
• Analyzing the interplay between individual band properties and overall system behavior.

Main Results:

• Unequal band widths introduce two distinct length scales for quasi-particle profiles.
• An orbitally selective Mott transition and a surface dead layer form for the narrow band near critical interaction.
• Two distinct charge transfer regimes (surface/center to center/surface) were identified in the doped case, dependent on doping and relative charge accumulation.

Conclusions:

• The difference in band widths significantly impacts charge distribution and surface properties in multi-band systems.
• These findings are relevant for understanding charge accumulation at interfaces in multi-band strongly correlated materials.
• The study highlights the importance of considering individual band characteristics in inhomogeneous correlated electron systems.