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In iron-based superconductors, the superconducting state is usually observed in close proximity to an electronic Ising-nematic phase, where the four-fold crystalline rotation symmetry is spontaneously broken. Upon doping or pressure, the critical temperature for the nematic phase is suppressed down to zero, revealing a putative Ising-nematic quantum critical point. Interestingly, the finite temperature electrical transport properties deviate strongly from standard Fermi liquid behavior, showing the crucial role played by the critical fluctuations.
In this talk, I will first derive a generalized kinetic equation valid in a broad temperature regime near the quantum critical point using the memory matrix approach. Next, I discuss several current-relaxation mechanisms and how they lead to very rich features in the temperature scaling of dc electrical resistivity beyond what has been studied in the literature. Finally I will discuss low frequency Raman scattering, in particular the onset of a quasi-elastic peak due to critical fluctuations.
References
[1] Xiaoyu Wang and Erez Berg, Phys. Rev. B 99, 235136 (2019)
[2] Xiaoyu Wang and Erez Berg, arXiv: 2011.01818 (2020)
Xiaoyu Wang holds a Dirac Fellowship for postdoctoral research in the National High Magnetic Field Lab in Tallahassee, Florida. In 2010, He obtained undergraduate degree in Electrical Engineering in Shanghai Jiao Tong University. He moved on to University of Minnesota, Twin Cities, and obtained a PhD degree in theoretical condensed matter physics in 2017. Prior to his current position, he spent two years as a postdoctoral researcher in the James Frank Institute in University of Chicago. His primary research interest is in strongly correlated electron systems, in particular topics associated with quantum critical phenomena and magic-angle twisted bilayer graphene.
Here is the Zoom link if you prefer to join us remotely:
https://zoom.com.cn/j/69928847943
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