Julku Aleksi, Peotta Sebastiano, Vanhala Tuomas I, Kim Dong-Hee, Törmä Päivi
COMP Centre of Excellence, Department of Applied Physics, Aalto University School of Science, FI-00076 Aalto, Finland.
Department of Physics and Photon Science, School of Physics and Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
Phys Rev Lett. 2016 Jul 22;117(4):045303. doi: 10.1103/PhysRevLett.117.045303.
The ground state and transport properties of the Lieb lattice flat band in the presence of an attractive Hubbard interaction are considered. It is shown that the superfluid weight can be large even for an isolated and strictly flat band. Moreover the superfluid weight is proportional to the interaction strength and to the quantum metric, a band structure quantity derived solely from the flat-band Bloch functions. These predictions are amenable to verification with ultracold gases and may explain the anomalous behavior of the superfluid weight of high-T_{c} superconductors.
考虑了存在吸引性哈伯德相互作用时利布晶格平带的基态和输运性质。结果表明，即使对于孤立且严格的平带，超流权重也可能很大。此外，超流权重与相互作用强度以及量子度量成正比，量子度量是一个仅由平带布洛赫函数导出的能带结构量。这些预测适合用超冷气体进行验证，并且可能解释高温超导体超流权重的反常行为。
