On the BCS-BEC Crossover in the 2D Asymmetric Attractive Hubbard Model

• Authors: A. Kujawa-Cichy
• Languages of publication: EN

Abstracts

EN

We analyze the evolution from the weak coupling (BCS-like limit) to the strong coupling limit of tightly bound local pairs in the 2D asymmetric attractive Hubbard model, in the presence of the Zeeman magnetic field (h). The broken symmetry Hartree approximation is used. We also apply the Kosterlitz-Thouless scenario to determine the phase coherence temperatures. We obtain that for the spin dependent hopping integrals (t^{↑} ≠ t^{↓}) the homogeneous polarized superfluid (SC_{M}) phase in the ground state for the strong attraction and lower filling can be stabilized. We find a topological quantum phase transition (the Lifshitz type) from the unpolarized superfluid phase (SC_0) to SC_{M} and tricritical point in the (h - μ) and spin polarization (P) vs. attraction (U < 0) ground state phase diagrams. The finite temperatures phase diagrams for t^{↑} ≠ t^{↓} are constructed.

Keywords

EN

71.10.Fd; 74.20.Rp; 71.27.+a; 71.10.Hf

Discipline

• 71.27.+a: Strongly correlated electron systems; heavy fermions
• 71.10.Fd: Lattice fermion models (Hubbard model, etc.)
• 71.10.Hf: Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems
• 74.20.Rp: Pairing symmetries (other than s-wave)

• Journal: Acta Physica Polonica A
• Year: 2012
• Volume: 121
• Issue: 5-6
• Pages: 1066-1069

Dates

published

2012-05

Contributors

author

A. Kujawa-Cichy

• Solid State Theory Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

References

• 1. M.W. Zwierlein, J. Abo-Shaeer, A. Schirotzek, C. Schunck, W. Ketterle, Nature 435, 1047 (2005)
• 2. M.W. Zwierlein, A. Schirotzek, C.H. Schunck, W. Ketterle, Science 311, 492 (2006)
• 3. G.B. Partridge, W. Li, R.I. Kamar, Y. Liao, R.G. Hulet, Science 311, 503 (2006)
• 4. D.E. Sheehy, L. Radzihovsky, Phys. Rev. Lett. 96, 060401 (2006)
• 5. G. Sarma, J. Phys. Chem. Solids 24, 1029 (1963)
• 6. W.V. Liu, F. Wilczek, Phys. Rev. Lett. 90, 047002 (2003)
• 7. W.V. Liu, F. Wilczek, P. Zoller, Phys. Rev. A 70, 033603 (2004)
• 8. M. Iskin, C.A.R.S. de Melo, Phys. Rev. Lett. 97, 100404 (2006)
• 9. M. Iskin, C.A.R.S. de Melo, Phys. Rev. A 76, 013601 (2007)
• 10. M.M. Parish, F.M. Marchetti, A. Lamacraft, B.D. Simons, Phys. Rev. Lett. 98, 160402 (2007)
• 11. M.M. Parish, F.M. Marchetti, A. Lamacraft, B.D. Simons, Nature Phys. 3, 124 (2007)
• 12. A. Kujawa-Cichy, Acta Phys. Pol. A 118, 423 (2010)
• 13. A. Kujawa-Cichy, R. Micnas, in preparation
• 14. A. Kujawa-Cichy, R. Micnas, Europhys. Lett. 95, 37003 (2011)
• 15. A. Kujawa, R. Micnas, Acta Phys. Pol. A 114, 43 (2008)
• 16. A. Kujawa, R. Micnas, Acta Phys. Pol. A 115, 138 (2009)
• 17. S. Robaszkiewicz, R. Micnas, K.A. Chao, Phys. Rev. B 23, 1447 (1981)
• 18. M.A. Cazalilla, A.F. Ho, T. Giamarchi, Phys. Rev. Lett. 95, 226402 (2005)
• 19. R. Micnas, S. Robaszkiewicz, Phys. Rev. B 45, 9900 (1992)
• 20. R. Micnas, S. Robaszkiewicz, T. Kostyrko, Phys. Rev. B 52, 6863 (1995)
• 21. R. Micnas, J. Ranninger, S. Robaszkiewicz, Rev. Mod. Phys. 62, 113 (1990)
• 22. T.-L. Dao, A. Georges, M. Capone, Phys. Rev. B 76, 104517 (2007)

Identifiers

DOI

10.12693/APhysPolA.121.1066