arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2011.06598cond-mat.supr-concond-mat.str-el
收藏

绝缘体到超导体转变的谱函数

Spectral functions across an Insulator to Superconductor Transition

Tamaghna Hazra, Nandini Trivedi, Mohit Randeria

摘要:

在费米子间具有吸引相互作用的最小两带模型中,我们用量子蒙特卡罗(QMC)方法计算了单粒子和双粒子激发能隙、带相关谱函数、超流密度和压缩性.我们发现费米和玻色绝缘相在单粒子谱函数中具有明显的初始配对特征,超导态具有三种不同的谱函数:(i)两个带都表现出“BCS”行为,其中最小能隙轨迹出现在下面费米表面的闭合轮廓上;(ii)两个带都表现出“BEC”行为,其中最小能隙轨迹出现在一点上;以及(iii)频带选择性光谱特性,其中一个频带显示“BCS”,而另一个频带显示“BEC”行为。在大的相互作用,我们发现一个莫特阶段的横档玻色子中的填充是一个玻色子的每两个网站,一半的典型密度约束莫特绝缘体。

英文摘要:

In a minimal 2-band model with attractive interactions between fermions, we calculate the gap to single and two-particle excitations, the band-dependent spectral functions, the superfluid density and compressibility using quantum Monte Carlo (QMC) methods. We find Fermi and Bose insulating phases with signatures of incipient pairing evident in the single-particle spectral functions, and a superconducting state with three different spectral functions: (i) both bands show "BCS" behavior in which the minimum gap locus occurs on a closed contour on the underlying Fermi surface; (ii) both bands show "BEC" behavior in which the minimum gap occurs at a point; and (iii) band selective spectral characteristics, in which one band shows "BCS" while the other shows "BEC" behavior. At large interactions, we find a Mott phase of rung bosons in which the filling is one boson for every two sites, half the typical density constraint for Mott insulators.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑