School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, Virginia 22030, USA.
Phys Rev Lett. 2012 Apr 6;108(14):145301. doi: 10.1103/PhysRevLett.108.145301. Epub 2012 Apr 2.
The recent experimental realization of dipolar Fermi gases near or below quantum degeneracy provides an opportunity to engineer Hubbard-like models with long-range interactions. Motivated by these experiments, we chart out the theoretical phase diagram of interacting dipolar fermions on the square lattice at zero temperature and half filling. We show that, in addition to p-wave superfluid and charge density wave order, two new and exotic types of bond order emerge generically in dipolar fermion systems. These phases feature homogeneous density but periodic modulations of the kinetic hopping energy between nearest or next-nearest neighbors. Similar, but manifestly different, phases of two-dimensional correlated electrons have previously only been hypothesized and termed "density waves of nonzero angular momentum." Our results suggest that these phases can be constructed flexibly with dipolar fermions, using currently available experimental techniques.
最近在接近或低于量子简并的条件下实现的偶极费米气体为工程具有长程相互作用的 Hubbard 型模型提供了机会。受这些实验的启发，我们在零温半满填充的情况下绘制出了二维正方晶格上相互作用的偶极费米子的理论相图。我们表明，除了 p 波超流和电荷密度波序之外，偶极费米子系统中通常还会出现两种新的奇异键序。这些相具有均匀的密度，但最近邻或次近邻之间的动力学跳跃能会发生周期性调制。以前，只有二维关联电子的类似但明显不同的相被假设并称为“非零角动量密度波”。我们的结果表明，使用当前可用的实验技术，这些相可以灵活地用偶极费米子来构建。
