【预告】中国人民大学李涛教授：Three observations on the ARPES data of ...

直播二维码

此次报告由北京师范大学物理学系主办，于2020年11月06日10:00开始，授权蔻享学术进行网络直播。

主题：Three observations on the ARPES data of the cuprate superconductors—what the AF spin fluctuation can do and what it cannot
主讲人：李涛 教授
单位：中国人民大学时间：2020年11月06日 10:00
主办方：北京师范大学物理学系

报告摘要

We discuss the origin of the pseudogap phenomena in the cuprate superconductors by analyzing three recent ARPES observations from the perspective of the spin-Fermion model. Firstly, we show that the recent observation of the vanishing of the pseudogap around (π, 0) in the electron-doped cuprate Prl.3-xLa0.7CexCuO4 is consistent with the AF band folding picture of the pseudogap in the electron-doped cuprates, provided that we assume a strongly momentum dependent quasi-particle scattering rate on the Fermi surface^{[1, 2]}. Secondly, we argue that the pseudogap in the hole-doped cuprates is unlikely an AF band folding gap, since the spin fluctuation in the hole-doped cuprates is much more short-ranged and dynamical in nature than that in the clectron-doped cuprates. In particular, we show that electron pairing is indispensable to eliminate the Fermi level crossing along (π, 0)-(π, π) in a way that is consistent with the ARPES observation in the under-doped Bi-2201 system around T*^{[3, 4]}. Nevertheless, we find that the AF spin fluctuation in the hole-doped cuprates is responsible for the emergence of the broad high energy hump structure in the anti-nodal region, and the mismatch between the back-bending momentum of the hump maximum and the underlying Fermi momentum along (π, 0)-(π, π), and in particular, the extremely flatness of the anti-nodal quasi-particle dispersion in the superconducting state^{[5, 6]}. We argue that the particle-hole symmetry breaking should better be studied in the energy space, rather than in the momentum space^[3]. Lastly, we show that the recent observation of the critical behavior at the pseudogap end point is consistent with the spin-Fermion picture^{[7, 8]}, even though the local spin in the cuprates is far from critical at such a high doping level, if one note the singular AF response of the quasi-particle system at the VHS doping. 

[1] Hario et al, arXiv: 1801 .04147.

[2] Tao Li and Da-Wei Yao, arXiv: 1803.08226 and EPL(2018).

[3] Hashimoto et al, Nat. Phys. 6, 414 (2010).

[4] Tao Li and Da-Wei Yao, arXiv: 1805.05530.

[5] Rui-Hua He et al Science 331, 1579 (2011).

[6] Tao Li and Da-Wei Yao, arXiv: 1805.04883. 

[7] Michon et al, arXiv: 1804.08502.

[8] Tao Li, arXiv: 1805.06395.

主讲人介绍

李涛，中国科学技术大学物理系低温物理专业本科、硕士。北京大学物理系凝聚态物理专业博士。清华大学高等研究院博士后、副研究员。2005年起担任中国人民大学物理系教授。主要从事高温超导机理和量子磁性的基础理论研究。研究方法包括低能有效理论，变分蒙特卡洛模拟以及唯象理论分析。对于量子自旋液体的变分搜索和低能有效理论构造，强关联电子系统动力学谱的变分构造和算法发展，以及高温超导体电子能谱的唯象理论分析有长期和较深入的研究。

编辑：冯春丽

—— ——往期精彩回顾—— ——● 直播回放：北京师范大学樊京芳副教授：Statistical Physics Approaches to the ...● 化学物理青年论坛 | 2020理论与计算化学研讨会

● 直播回放：听诺奖得主史蒂芬·温伯格讲有效场论

● 直播回放：北京大学李彦教授、威斯康星大学麦迪逊分校金松教授精彩学术报告 | iCANX Talks● 直播回放：华为开发者大赛@量子计算软件创新大赛

为满足更多科研工作者的需求，蔻享平台开通了各科研领域的微信交流群。进群请添加微信18019902656（备注您的科研方向）小编拉您入群哟！蔻享网站www.koushare.com已开通自主上传功能，期待您的分享！

---

欢迎大家提供各类学术会议或学术报告信息，以便广大科研人员参与交流学习。

联系人：李盼 18005575053（微信同号）戳这里，观看精彩直播哟！