Size and shape of Mott regions for fermionic atoms in a two-dimensional optical lattice
| Autor: | Raimundo R. dos Santos, Thereza Paiva, Tiago Mendes-Santos |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Condensed Matter::Quantum Gases
Physics Optical lattice Condensed matter physics Diagram FOS: Physical sciences Mott scattering Atomic and Molecular Physics and Optics Mott transition Lanczos resampling Quantum Gases (cond-mat.quant-gas) Compressibility Condensed Matter::Strongly Correlated Electrons Boundary value problem Metal–insulator transition Condensed Matter - Quantum Gases |
| Zdroj: | Physical Review A. 91 |
| ISSN: | 1094-1622 1050-2947 |
| Popis: | We investigate the harmonic-trap control of size and shape of Mott regions in the Fermi Hubbard model on a square optical lattice. The use of Lanczos diagonalization on clusters with twisted boundary conditions, followed by an average over 50-80 samples, drastically reduce finite-size effects in some ground state properties; calculations in the grand canonical ensemble together with a local-density approximation (LDA) allow us to simulate the radial density distribution. We have found that as the trap closes, the atomic cloud goes from a metallic state, to a Mott core, and to a Mott ring; the coverage of Mott atoms reaches a maximum at the core-ring transition. A `phase diagram' in terms of an effective density and the on-site repulsion is proposed, as a guide to maximize the Mott coverage. We also predict that the usual experimentally accessible quantities, the global compressibility and the average double occupancy (rather, its density derivative) display detectable signatures of the core-ring transition. Some spin correlation functions are also calculated, and predict the existence N\'eel ordering within Mott cores and rings. Comment: 5 pages, 6 figures |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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