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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Dynamical cluster approximation study of the anisotropic two-orbital Hubbard model
Hunpyo Lee1, Yu-Zhong Zhang, Harald O Jeschke
1Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
Physical Review Letters
|April 7, 2010
Summary
This study explores the two-orbital Hubbard model, revealing an orbital-selective Mott transition (OSMT) at larger cluster sizes. Smaller clusters stabilize a band insulator due to artificial ordering.
Area of Science:
- Condensed Matter Physics
- Quantum Many-Body Theory
- Materials Science
Background:
- The two-orbital Hubbard model is crucial for understanding correlated electron systems.
- Orbital-selective Mott transitions (OSMT) are key phenomena in materials with multiple orbitals.
- Understanding the interplay of spatial fluctuations and bandwidth differences is essential.
Purpose of the Study:
- Investigate the properties of a two-orbital Hubbard model on a square lattice.
- Explore the influence of short-range spatial fluctuations on metal-insulator transitions.
- Determine the conditions for the occurrence of orbital-selective Mott transitions (OSMT) as a function of cluster size.
Main Methods:
- Utilized the dynamical cluster approximation (DCA).
- Combined DCA with a continuous-time quantum Monte Carlo algorithm.
- Analyzed the model for varying cluster sizes (N{c}=2 and N{c}=4).
Main Results:
- For N{c}=2, no OSMT was observed; a band insulator state stabilized due to artificial local ordering.
- For N{c}=4, DCA calculations indicated five distinct phases.
- An orbital-selective Mott transition (OSMT) phase was stabilized for N{c}=4, arising from competing factors.
Conclusions:
- The cluster size significantly impacts the emergent phases in the two-orbital Hubbard model.
- Spatial fluctuations and differing orbital bandwidths cooperate to stabilize complex phases, including OSMT.
- The study sheds light on the mechanisms governing gap opening in strongly correlated systems.
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