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arXiv 1508.04871cond-mat.supr-con
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反铁磁Mott态的掺杂光谱演化

Spectral evolution with doping of an antiferromagnetic Mott state

Huan-Kuang Wu, Ting-Kuo Lee

摘要:

自从发现半填充铜氧化物是一种莫特绝缘体以来,未占据态在化学势以上的激发光谱引起了人们的广泛关注。有许多理论工作使用不同的数值技术来研究这个问题,但许多人得出了不同的结论。其中一个原因是缺乏非常详细的高分辨率实验结果来与理论进行比较。最近,扫描隧道光谱(STS)的\cite{cai2015visualizing,ye2013visualizing}轻掺杂莫特绝缘体与反铁磁(AFM)秩序发现的存在下,在间隙状态的能量为半个eV以上的化学势。掺杂的测量光谱特性与早期的理论工作不太一致。在变分蒙特卡罗(VMC)计算的基础上,采用对角化方法研究了哈伯德模型(HM)中AFM Mott态随掺杂空穴浓度的演化.我们的研究结果发现,在间隙状态的行为与STS报告的相似。这些在间隙状态获得了大量的动力学谱权重转移从上哈伯德带。随着掺杂量的增加,带隙态向化学势方向移动,光谱权重也随之增加。我们的结果还提供了关于这些带隙态的能量尺度与库仑耦合强度U的关系的信息。

英文摘要:

Since the discovery of half-filled cuprate to be a Mott insulator, the excitation spectra above the chemical potential for the unoccupied states has attracted many research attentions. There were many theoretical works using different numerical techniques to study this problem, but many have reached different conclusions. One of the reasons is the lack of very detailed high-resolution experimental results for the theories to be compared with. Recently, the scanning tunneling spectroscopy (STS)\cite{cai2015visualizing,ye2013visualizing} on lightly doped Mott insulator with an antiferromagnetic (AFM) order found the presence of in-gap states with energy of order half an eV above the chemical potential. The measured spectral properties with doping are not quite consistent with earlier theoretical works. In this paper we perform a diagonalization method on top of the variational Monte Carlo (VMC) calculation to study the evolution of AFM Mott state with doped hole concentration in the Hubbard model (HM). Our results found in-gap states that behave similarly with ones reported by STS. These in-gap states acquire a substantial amount of dynamical spectral weight transferred from the upper Hubbard band. The in-gap states move toward chemical potential with increasing spectral weight as doping increases. Our result also provides information about the energy scale of these in-gap states in relation with the coulomb coupling strength U.

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。

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