中文

Journal of Shanghai University >

2019 , Vol. 25 >Issue 6: 914 - 923

DOI: https://doi.org/10.12066/j.issn.1007-2861.2150

Research Articles

Thermo dynamic properties of spin-orbit-coupled two-dimensional Fermi gases

Expand
  • Institute of Theoretical Physics, Shanxi University, Taiyuan 030006, China

Received date: 2019-05-05

  Online published: 2019-12-31

Fold

Abstract

Using the mean-field theory, we investigate the thermodynamic properties of two-dimensional Fermi gases with spin-orbit coupling and Zeeman field. By solving the gap and particle-number equations, we discuss the influences of spin-orbit coupling and Zeeman field on the isothermal compressibility, pressure, superfluid order parameter and entropy, and find some anomalous behaviors different from the three-dimensional systems. It is indicated that due to the influences of spin-orbit coupling and Zeeman field, the isothermal compressibility and the pressure do not change with the interatomic interactions in the Bose-Einstein condensate (BEC) limits, which is distinctly different from the case of three-dimensional systems, where these two thermodynamic quantities change linearly with the interactions. In the Bardeen, Cooper and Schrieffer (BCS) limits, the isothermal compressibility and the pressure sensitively depends on the strengths of spin-orbit coupling and Zeeman field. In appropriate parameters, by adjusting the spin-orbit coupling and the Zeeman field we also observe non-monotonic changes of the isothermal compressibility, pressure, superfluid order parameter and entropy. In addition, it is found that the spin-orbit coupling and the Zeeman field leads to opposite changes of the entropy between the normal phase and the superfluid phase.

Key words： spin-orbit coupling; superfluid; isothermal compressibility; entropy; pressure

Cite this article

Chenggong LIANG, Yunbo ZHANG . Thermo dynamic properties of spin-orbit-coupled two-dimensional Fermi gases[J]. Journal of Shanghai University, 2019 , 25(6) : 914 -923 . DOI: 10.12066/j.issn.1007-2861.2150

References

[1] Bloch I, Dalibard J, Zwerger W . Many-body physics with ultracold gases[J]. Reviews of modern physics, 2008,80(3):885-964.
[2] O'hara K M, Hemmer S L, Gehm M E , et al. Observation of a strongly interacting degenerate Fermi gas of atoms[J]. Science, 2002,298(5601):2179-2182.
[3] Inouye S, Andrews M R, Stenger J , et al. Observation of Feshbach resonances in a Bose-Einstein condensate[J]. Nature, 1998,392(6672):151-154.
[4] Bertaina G, Giorgini S . BCS-BEC crossover in a two-dimensional Fermi gas[J]. Phys Rev Lett, 2011,106(11):110403.
[5] Bauer M, Parish M, Enss T . Universal equation of state and pseudogap in the two-dimensional Fermi gas[J]. Phys Rev Lett, 2014,112(13):135302.
[6] Anderson E R, Drut J E . Pressure, compressibility, and contact of the two-dimensional attractive Fermi gas[J]. Phys Rev Lett, 2015,115(11):115301.
[7] J?rdens R, Strohmaier N, Günter K , et al. A Mott insulator of fermionic atoms in an optical lattice[J]. Nature, 2008,455(7210):204-207.
[8] Scarola V W, Pollet L, Oitmaa J , et al. Discerning incompressible and compressible phases of cold atoms in optical lattices[J]. Phys Rev Lett, 2009,102(13):135302.
[9] Taie S, Yamazaki R, Sugawa S , et al. An SU (6) Mott insulator of an atomic Fermi gas realized by large-spin Pomeranchuk cooling[J]. Nature Physics, 2012,8(11):825-830.
[10] Schneider U, Hackermüller L, Will S , et al. Metallic and insulating phases of repulsively interacting fermions in a 3D optical lattice[J]. Science, 2008,322(5907):1520-1525.
[11] Zhou Q, Kato Y, Kawashima N , et al. Direct mapping of the finite temperature phase diagram of strongly correlated quantum models[J]. Phys Rev Lett, 2009,103(8):085701.
[12] Nozadze D, Trivedi N . Compressibility as a probe of quantum phase transitions in topological superconductors[J]. Phys Rev B, 2016,93(6):064512.
[13] Khatami E, Mikelsons K, Galanakis D , et al. Quantum criticality due to incipient phase separation in the two-dimensional Hubbard model[J]. Phys Rev B, 2010,81(20):201101.
[14] Gull E, Parcollet O, Werner P , et al. Momentum-sector-selective metal-insulator transition in the eight-site dynamical mean-field approximation to the Hubbard model in two dimensions[J]. Phys Rev B, 2009,80(24):245102.
[15] Lin Y J, Jiménez-garcía K, Spielman I B . Spin-orbit-coupled Bose-Einstein condensates[J]. Nature, 2011,471(7336):83-86.
[16] Wang P, Yu Z Q, Fu Z , et al. Spin-orbit coupled degenerate Fermi gases[J]. Phys Rev Lett, 2012,109(9):095301.
[17] Cheuk L W, Sommer A T, Hadzibabic Z , et al. Spin-injection spectroscopy of a spin-orbit coupled Fermi gas[J]. Phys Rev Lett, 2012,109(9):095302.
[18] Huang L, Meng Z, Wang P , et al. Experimental realization of two-dimensional synthetic spin--orbit coupling in ultracold Fermi gases[J]. Nature Physics, 2016,12(6):540-544.
[19] Wu Z, Zhang L, Sun W , et al. Realization of two-dimensional spin-orbit coupling for Bose-Einstein condensates[J]. Science, 2016,354(6308):83-88.
[20] Chin C, Grimm R, Julienne P , et al. Feshbach resonances in ultracold gases[J]. Reviews of Modern Physics, 2010,82(2):1225-1286.
[21] K?hler T, Góral K, Julienne P S . Production of cold molecules via magnetically tunable Feshbach Resonances[J]. Reviews of modern physics, 2006,78(4):1311-1361.
[22] Giorgini S, Pitaevskii L P, Stringari S . Theory of ultracold atomic Fermi gases[J]. Reviews of Modern Physics, 2008,80(4):1215-1274.
[23] Morsch O, Oberthaler M . Dynamics of Bose-Einstein condensates in optical lattices[J]. Reviews of modern physics, 2006,78(1):179-215.
[24] Lewenstein M, Sanpera A, Ahufinger V , et al. Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond[J]. Advances in Physics, 2007,56(2):243-379.
[25] Galitski V, Spielman I B . Spin-orbit coupling in quantum gases[J]. Nature, 2013,494(7435):49-54.
[26] Manchon A, Koo H C, Nitta J , et al. New perspectives for Rashba spin-orbit coupling[J]. Nature materials, 2015,14(9):871-882.
[27] Goldman N, Juzeli$\bar{u}$as G, ?hberg P , et al. Light-induced gauge fields for ultracold atoms[J]. Reports on Progress in Physics, 2014,77(12):126401.
[28] Dalibard J, Gerbier F, Juzeli$\bar{u}$as G , et al. Colloquium: Artificial gauge potentials for neutral atoms[J]. Reviews of Modern Physics, 2011,83(4):1523-1543.
[29] Yi W, Zhang W, Cui X L . Pairing superfluidity in spin-orbit coupled ultracold Fermi gases[J]. Science China Physics, Mechanics & Astronomy, 2015,58(1):1-11.
[30] Liang C G, Huang Y X, Liu F H , et al. Anomalous isothermal compressibility in spin-orbit coupled degenerate Fermi gases [EB/OL]. ( 2019 -03-02)[2019-04-26]. .
[31] Liang C G, Huang Y X, Liu F H , et al. Isothermal compressibility in Fermi gases in an optical lattice[J]. Physical Review A, 2019,99(2):023624.
[32] Murthy P A, Boettcher I, Bayha L , et al. Observation of the Berezinskii-Kosterlitz-Thouless phase transition in an ultracold Fermi gas[J]. Physical review letters, 2015,115(1):010401.
[33] Dagotto E . Correlated electrons in high-temperature superconductors[J]. Reviews of Modern Physics, 1994,66(3):763.
[34] Geim A K, Novoselov K S . The rise of graphene[J]. Nature Materials, 2007,6:183-197.
[35] Hasan M Z, Kane C L . Colloquium: topological insulators[J]. Reviews of modern physics, 2010,82(4):3045-3067.
[36] Fenech K, Dyke P, Peppler T , et al. Thermodynamics of an attractive 2D Fermi gas[J]. Physical review letters, 2016,116(4):045302.
[37] Xu J P, Wang M X, Liu Z L , et al. Experimental detection of a Majorana mode in the core of a magnetic vortex inside a topological insulator-superconductor Bi$_2$Te$_3$/NbSe$_2$ heterostructure[J]. Physical review letters, 2015,114(1):017001.
[38] Nadj-Perge S, Drozdov I K, Li J , et al. Observation of Majorana fermions in ferromagnetic atomic chains on a superconductor[J]. Science, 2014,346(6209):602-607.
[39] Zhang H, Liu C X, Gazibegovic S , et al. Quantized majorana conductance[J]. Nature, 2018,556(7699):74-79.
[40] Das A, Ronen Y, Most Y , et al. Zero-bias peaks and splitting in an Al-InAs nanowire topological superconductor as a signature of Majorana fermions[J]. Nature Physics, 2012,8(12):887-895.
[41] Chen G, Gong M, Zhang C . BCS-BEC crossover in spin-orbit-coupled two-dimensional Fermi gases[J]. Physical Review A, 2012,85(1):013601.
Options
Outlines

/

〈 〉