Year: 2006
Type: article
Abstract: We investigate the Kondo lattice model on two-dimensional (2D) clusters using the finite temperature Lanczos method. The temperature dependence of thermodynamic and correlations functions are systematically studied for various Kondo couplings ${J}_{\mathrm{K}}$. The ground state value of the total local moment is presented as well. Finally, the phase diagrams of the finite clusters are constructed for periodic and open boundary conditions. For the two boundary conditions, two different regimes are found for small ${J}_{\mathrm{K}}∕t$, depending on the distribution of noninteracting conduction electron states. If there are states within ${J}_{\mathrm{K}}$ around the Fermi level, two energy scales, linear and quadratic in ${J}_{\mathrm{K}}$, exist. The former is associated with the onsite screening and the latter with the RKKY interaction. If there are no states within ${J}_{\mathrm{K}}$ around the Fermi level, the only energy scale is that of the RKKY interaction. Our results imply that the form of the electron density of states (DOS) plays an important role in the competition between the Kondo screening and the RKKY interaction. The former is stronger if the DOS is larger around the Fermi level, while the latter is less sensitive to the form of the DOS.
Source: Physical Review B
Authors: I. Zerec, B. Schmidt, P. Thalmeier
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1584703231