[论文解读] Elucidation of the origins of HTSC transport behaviour and quantum oscillations

J. A. Wilson|ArXiv.org|Nov 19, 2008

Physics of Superconductivity and Magnetism参考文献 7被引用 3

一句话总结

本文通过非均匀、混合价态系统在莫特-安德森转变附近的局域对与玻色子-费米子共振框架，重新诠释了高温超导体（HTSC）输运和量子振荡数据。文中指出，观测到的振荡并非源于传统费米液体中的费米面，而是源于二维对角电荷条纹阵列中的磁通子晶格有序，且在强磁场下，磁通量子有效加倍至 h/e。

ABSTRACT

A detailed exposition is made of recent transport and 'quantum oscillation' results from HTSC systems covering the full range from overdoped to underdoped material. This now very extensive and high quality data set is interpreted here within the framework developed by the author of local pairs and boson-fermion resonance, arising in the context of negative-U behaviour in an inhomogeneous electronic environment. The strong inhomogeneity comes with the mixed-valent condition of these materials, which when underdoped lie in close proximity to the Mott-Anderson transition. The observed intense scattering is presented as resulting from pair formation and electron-boson collisions in the resonant crossover circumstance. The high level of scattering brings the systems to incoherence in the pseudogapped state, p < pc (= 0.183). In a high magnetic field the striped partition of the inhomogeneous charge distribution is much strengthened and regularized. Magnetization and resistance oscillations, of period dictated by the favoured positioning of the square fluxon array within the real space environment of the diagonal 2D charge striping array, are demonstrated to be responsible for the recently reported behaviour hitherto widely attributed to the quantum oscillation response of a much more standard Fermi liquid condition. A detailed analysis embracing all the experimental data serves to indicate that in the given conditions of very high field, low temperature, 2D-striped, underdoped, d-wave superconducting, HTSC material the flux quantum becomes doubled to h/e.

研究动机与目标

• 解决长期以来关于欠掺杂铜氧化物中量子振荡的谜题，这些现象与传统费米液体理论的预期相矛盾。
• 解释HTSC材料在过掺杂至欠掺杂区域中输运非定域性与赝能隙行为的起源。
• 证明观测到的振荡源于二维条纹电荷环境中的磁通子晶格动力学，而非费米面。
• 在局域配对与共振散射的单一框架内统一描述输运、量子振荡与非定域性现象。

提出的方法

• 分析了从过掺杂到欠掺杂HTSC材料的广泛实验输运与量子振荡数据。
• 应用基于局域对与非均匀电子环境中玻色子-费米子共振的理论框架。
• 将系统建模为接近莫特-安德森转变，由于混合价态与电荷非均匀性，存在强烈的电子-玻色子散射。
• 引入一种共振交叉机制，其中配对形成与散射共同导致赝能隙态（p < pc = 0.183）中的非定域性。
• 预测强磁场可将非均匀电荷分布规整化为对角2D条纹，稳定正方形磁通子晶格。
• 推导出由于条纹阵列的空间周期性，磁通量子有效变为h/e，导致振荡周期由这种实空间结构决定。

实验结果

研究问题

• RQ1 如果非费米面，是什么导致了欠掺杂HTSC材料中观测到的量子振荡？
• RQ2 为何系统在欠掺杂区域表现出输运非定域性与赝能隙行为？
• RQ3 电荷条纹与磁场的存在如何影响磁通子晶格与量子振荡周期？
• RQ4 高场实验中磁通量子表观加倍至h/e的起源是什么？
• RQ5 观测到的输运与振荡行为能否通过局域配对与共振散射机制而非费米液体模型得到一致解释？

主要发现

• 高磁场下观测到的量子振荡源于对角2D电荷条纹阵列中磁通子的周期性排列，而非费米面。
• 由于条纹结构的空间周期性，磁通量子有效加倍至h/e，该周期性调制了磁通子晶格。
• 赝能隙态（p < 0.183）中的输运非定域性源于局域对形成与电子-玻色子共振引起的强烈散射。
• 强磁场增强并规整非均匀电荷分布，稳定了有序的磁通子晶格。
• 整个数据集，包括电阻与磁化率振荡，均可由所提出的非均匀、共振配对模型一致解释。
• 该框架在局域配对与共振散射的单一机制下，统一了赝能隙行为、非定域性与量子振荡。