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arXiv 1804.09271cond-mat.str-elcond-mat.supr-con
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莫特绝缘体与d波高温超导体的直接联系--自能极的连续演化

Direct Connection between Mott Insulator and d-Wave High-Temperature Superconductor Revealed by Continuous Evolution of Self-Energy Poles

Shiro Sakai, Marcello Civelli, Masatoshi Imada

摘要:

铜氧化物的高温超导性是在母体莫特绝缘体中掺杂载流子后产生的。然而,这一公认的事实却没有一个微观的解释。在这里,我们表明,缺少的环节是在能量动量空间的自能极。它的不断演变与掺杂直接连接的莫特绝缘体和高温超导。我们通过数值研究非常小的掺杂区域接近莫特绝缘相的标准模型铜氧化物,二维哈伯德模型。我们首先确定两个相关的自能结构的莫特绝缘体;极产生莫特间隙和一个相对较宽的峰产生所谓的瀑布结构,这是另一个后果的强相关性存在于莫特绝缘体。我们接下来揭示了当系统掺杂载流子时,莫特能隙极或瀑布结构(能量更接近费米能级的特征)直接将其自身转变为具有相同能量和动量的另一个自能极。产生超导性的反常自能恰好同时产生于这个能量-动量点。由此产生的自能极,解释为产生于一个隐藏的费米子激发,不断演变后进一步掺杂,大大提高了超导性。在临界温度以上,相同的自能极在正常状态下产生赝能隙。因此,我们阐明了一个统一的莫特物理机制,固有的莫特绝缘体的自能结构直接产生的高温超导性和赝能隙。

英文摘要:

The high-temperature superconductivity in copper oxides emerges when carriers are doped into the parent Mott insulator. This well-established fact has, however, eluded a microscopic explanation. Here we show that the missing link is the self-energy pole in the energy-momentum space. Its continuous evolution with doping directly connects the Mott insulator and high-temperature superconductivity. We show this by numerically studying the extremely small doping region close to the Mott insulating phase in a standard model for cuprates, the two-dimensional Hubbard model. We first identify two relevant self-energy structures in the Mott insulator; the pole generating the Mott gap and a relatively broad peak generating the so-called waterfall structure, which is another consequence of strong correlations present in the Mott insulator. We next reveal that either the Mott-gap pole or the waterfall structure (the feature at the energy closer to the Fermi level) directly transforms itself into another self-energy pole at the same energy and momentum when the system is doped with carriers. The anomalous self-energy yielding the superconductivity is simultaneously born exactly at this energy-momentum point. Thus created self-energy pole, interpreted as arising from a hidden fermionic excitation, continuously evolves upon further doping and considerably enhances the superconductivity. Above the critical temperature, the same self-energy pole generates a pseudogap in the normal state. We thus elucidate a unified Mott-physics mechanism, where the self-energy structure inherent to the Mott insulator directly gives birth to both the high-temperature superconductivity and pseudogap.

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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