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arXiv 1503.06372cond-mat.str-el
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自旋费米子模型中的超导和电荷密度波序:比较分析

Superconducting and charge-density-wave orders in the spin-fermion model: a comparative analysis

Yuxuan Wang, Andrey Chubukov

摘要:

我们目前的超导和电荷密度波订单的自旋涨落的情况下的铜氧化物的比较分析。自旋涨落交换导致d波超导性是众所周知的。最近有几个研究小组认为,同样的自旋介导的相互作用也可以解释在低掺杂铜酸盐中检测到的动量为$(Q,0)$或$(0,Q)$的电荷密度波序。这已经被质疑的基础上,电荷密度波通道混合费米表面上的嵌套和反嵌套区域的费米子,并且反嵌套区域中的费米子没有形成束缚态的自然趋势,即使相互作用是吸引的。我们表明,反嵌套是不是一个障碍,收费秩序,但要看到这一点需要超越传统的Eliashberg近似。我们表明,在完美的嵌套/antinesting的情况下,当热费米子的速度是平行或反平行的,在超导和电荷密度波通道的起始温度是可比的强度为任何磁关联长度$ξ$。超导$T_{\rm sc}$比$T_{\rm cdw}$大,但只是在数字上。当热费米子的速度不是严格平行/反平行时,$T_{\rm cdw}$随着$ξ$的减小而逐渐减小,并在某个临界$ξ$处消失。

英文摘要:

We present comparative analysis of superconducting and charge-density-wave orders in the spin-fluctuation scenario for the cuprates. That spin-fluctuation exchange gives rise to d-wave superconductivity is well known. Several groups recently argued that the same spin-mediated interaction may also account for charge-density-wave order with momenta $(Q,0)$ or $(0,Q)$, detected in underdoped cuprates. This has been questioned on the basis that charge-density-wave channel mixes fermions from both nested and anti-nested regions on the Fermi surface, and fermions in the anti-nested region do not have a natural tendency to form a bound state, even if the interaction is attractive. We show that anti-nesting is not an obstacle for charge order, but to see this one needs to go beyond the conventional Eliashberg approximation. We show that in the prefect nesting/antinesting case, when the velocities of hot fermions are either parallel or antiparallel, the onset temperatures in superconducting and charge-density-wave channels are of comparable strength for any magnetic correlation length $ξ$. The superconducting $T_{\rm sc}$ is larger than $T_{\rm cdw}$, but only numerically. When the velocities of hot fermions are not strictly parallel/antiparallel, $T_{\rm cdw}$ progressively decreases as $ξ$ decreases and vanishes at some critical $ξ$.

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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