报告人：冯世平 教授（北京师范大学）

时 间：2025年4月24日（周四）上午10:00

地 点：williamhill官网良乡校区，物理实验中心229会议室

摘要：

The transport experiments demonstrate a dramatic switch from the low-temperature linear in temperature (T-linear) resistivity in the overdoped strange-metal phase of cuprate superconductors to the low-temperature quadratic in temperature (T-quadratic) resistivity in the underdoped pseudogap phase, however, a consensus on the origin of this unusual switch is still lacking. Here the resistivity in the underdoped pseudogap phase of cuprate superconductors is investigated using the Boltzmann transport equation. The resistivity originates from the electron Umklapp scattering mediated by the spin excitation, however, the dominant contribution mainly comes from the antinodal umklapp scattering. In particular, a low temperature Tscale scales with D2p in the underdoped regime due to the opening of a momentum dependent spin pseudogap, where Dp is the minimal umklapp vector at the antinode. Moreover, this Tscale decreases with the increase of doping in the underdoped regime, and then is reduced to a very low temperature in the overdoped regime. In the underdoped regime, the resistivity is T-quadratic at the low temperatures below Tscale, where the strength of the T-quadratic resistivity weakens as the doping is raised. However, in the overdoped regime, the resistivity is T-linear at the low temperatures above Tscale. The results therefore show that the electron umklapp scattering from a spin excitation responsible for the low-temperature T-linear resistivity in the overdoped regime naturally produces the low-temperature T-quadratic resistivity in the underdoped regime resulting from the opening of a momentum dependent spin pseudogap.

简历：

冯世平教授，1978. 3-1982.１在北京师范大学物理系学习并获学士学位。1982. 3-1987. 7作为研究生继续在北京师范大学学习并获博士学位。1987. 10 -1989. 9在美国休斯敦大学超导物理研究中心做博士后研究工作。1990. 6被聘为北京师范大学物理系副教授。1992. 1- 994. 1在意大利里亚斯特国际理论物理中心合作研究。1994. 6被聘为北京师范大学物理系教授。2000. 9-2003. 7任北京师范大学物理系系主任。

冯世平教授主要从事于强关联多电子系统与高温超导电性的理论研究。在解释高温超导体的超导机理和反常物理性质方面做了一些有特色的研究工作，入选1994年度教育部《跨世纪优秀人才计划》，获1997年度香港求是科技基金会“杰出青年学者奖”，1998年被国家授予有突出贡献的中青年专家，2001年度获国家杰出青年基金资助。现兼任Chinese Physics和《物理学报》编委会成员。

联系方式：yangfan_blg@bit.edu.cn

邀请人： 杨帆

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承办单位：物理学院