strong correlation and unconventional superconductivity in alkali-doped fullerides

来源:国际功能材料量子设计中心
报告题目   strong correlation and unconventional superconductivity in alkali-doped fullerides
报告人   岳长明 助理教授
报告人单位   南方科技大学
报告时间   2023-11-13 15:00:00
报告地点   物质科研b楼0804会议室
主办单位   合肥微尺度物质科学国家研究中心、国际功能材料量子设计中心
报告介绍

报告摘要:

  the alkali-doped fullerides a3c60 (a = k, rb, cs) exhibit strong correlation and unconventional superconductivity (sc) in both bulk and thin films. we investigate the unconventional pairing mechanism in bulk a3c60 using dynamical mean-field theory (dmft) in the nambu formalism. the local orbital fluctuations are found to be substantially enhanced in the superconducting state and provide the pairing glue in a3c60. a lock-in phenomenon between the sc gap (fermionic) and the local orbital fluctuation energy (bosonic) is found, which is consistent with an experimentally observed universal linear relationship [1]. epitaxially grown k3 xc60 thin films exhibit a mott insulating state in the monolayer and a strong electron-hole doping asymmetry in the superconducting state in the trilayer [2], which asymmetry is absent in the three-dimensional bulk limit. by using dft dmft [3], the speaker will show that this doping asymmetry results from a substantial charge reshuffling from the top layer to the middle layer. the interlayer charge transfer and layer-selective metal-insulator transition result from the interplay between crystal field splittings, strong coulomb interactions, and an effectively negative hund coupling.

  if time is allowed, the speaker would like to report our recent progress in the analytic continuation of anomalous self-energy and its application in k3c60 [4] and cs3c60 [5], which paves the way for the theoretical study of momentum resolved spectra in the sc phase using quantum monte-carlo method.

 

[1] c. yue, s. hoshino, a. koga and p. werner, phys. rev. b 104, 075107 (2021)

[2] ming-qiang ren, et. al., phys. rev. lett. 124, 187001 (2020)

[3] c. yue, y. nomura, and p. werner, phys. rev. lett. 129, 066403 (2022)

[4] c. yue. and p. werner, arxiv: 2303.16888 (2023)

[5] c. yue. y. nomura, k. prassides, p. werner: arxiv: 2307, 04637 (2023).

 

报告人简介:

  岳长明,现任南方科技大学助理教授。博士毕业于中国科学院物理研究所,之后在瑞士fribourg大学从事博士后研究,从事凝聚态物理的计算与理论研究。研究方向主要为:发展量子多体方法如数值精确的连续时间量子蒙特卡罗方法,以研究碱金属掺杂的富勒烯、铱基、铁基、铜基等强关联电子体系的电子结构与输运性质、非常规超导的配对与增强机制,以及拓扑材料的理论预言。 研究成果发表于nature physics、 phys. rev. lett.、phys. rev. b、 comput. phys. commun. 等国际权威学术期刊,累计20多篇。

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