Disorder-induced charge-density-wave-superfluid transition in SU(N) Fermi systems
Disorder-induced charge-density-wave-superfluid transition in SU(N) Fermi systems
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SU(N) 费米系统中无序诱导的电荷密度波超流体跃迁
DOI：
10.1103/physreva.90.013632
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
川上則雄
中科院分区：
文献类型：
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作者：
阪井田賢;川上則雄
我们使用Bogoliubov-de Gennes方法在零温度下研究了具有无序的吸引费米系统，并特别关注了SU(3)情况。计算了二维方形晶格体系半填充时的电荷相关函数、超流体序参量的分布函数和自由能。从这些量的无序平均来看，我们发现无序触发了从电荷密度波（CDW）相到SF相的转变；无序抑制CDW秩序，使SF状态稳定。这种无序驱动的相变是一阶的，并且对于SU(3)系统是唯一的；对于无序的SU(2)系统，到目前为止还没有观察到它。我们从态的无序平均密度和粒子密度的分布函数出发，阐明了CDW-SF跃迁的性质，从而得到了基态相图。我们还解决了SU(4)的情况，发现CDW状态直接被驱动到安德森局域状态，但SF相不稳定。我们讨论一般情况下的预期结果。
We investigateattractive Fermi systems with disorder using a Bogoliubov-de Gennes method at zero temperature with particular focus on the SU(3) case. The charge correlation function, the distribution function of the superfluid (SF) order parameter, and the free energy are calculated for a two-dimensional square lattice system at half filling. From the disorder average of these quantities, we find that disorder triggers a transition from the charge-density-wave (CDW) phase to the SF phase; disorder suppresses the CDW order, making the SF state stable. This disorder-driven phase transition is of first order and is unique for SU(3) systems; it has not been observed for the disordered SU(2) systems studied so far. We elucidate the properties of the CDW-SF transition from the disorder-averaged density of states and the distribution function of the particle density and thus obtain the ground-state phase diagram. We also address the SU(4) case and find that the CDW state is driven directly to the Anderson localized state, but the SF phase is not stabilized. We argue what will be expected for genericcases.