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Condensed Matter / Biophysics Seminars

Fall 2022

Condensed Matter/Biophysics Seminars Mondays at 4:05pm in 2205 NPB


Committee: Yuxuan Wang, Xiao-Xiao Zhang and Purushottam Dixit


August 29

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September 5

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September 12

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September 19

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September 26

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October 3

  Speaker Chunjing Jia (UF Physics)
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October 10

  Speaker Andrey Chubukov (UMN)
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  Host Yuxuan Wang

October 17

  Speaker Armita Nourmohammad (University of Washington)
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October 24

  Speaker Richard Greene (University of Maryland)
  Title Strange metal transport, ferromagnetism and the Planckian scattering rate limit in electron-doped cuprates
  Abstract I will discuss recent transport studies on thin films of the electron-doped cuprate system La2-xCexCuO4 that exhibit strange metal transport in the normal state down to 35 mK. These results strongly suggest that the high-Tc superconductivity emerges from this strange metal normal state. The strange metal behavior is manifested as a linear-in-T resistivity from 35 mK to 20K and a ~T^2 resistivity from 50K to 400K over a range of doping above and below a Fermi surface reconstruction at x = 0.14 [1-2]. Other indications of strange metal behavior include a low temperature linear-in-H magnetoresistance and a low temperature lnT thermopower [3-5] over the same range of doping. At the present time these results have not been explained and they represent a challenge to the theory of the cuprates.

In addition, I will discuss a study of these films via a combination of dc conductivity and optical conductivity [6], which shows that the electron scattering rate far exceeds the conjectured Planckian bound on inelastic scattering at temperatures above 20K. This suggests that recent highly publicized claims of a Planckian bound on transport in solids are not universal and that the temperature dependence of the normal state resistivity of the cuprates remains an unexplained mystery. If time permits I will discuss experiments that suggest ferromagnetism exists below 4K for electron-doping beyond the superconducting dome [7].

References [1]. T. Sarkar et al., Phys. Rev. B 103, 224501 (2021) [2]. T. Sarkar et al., Phys. Rev. B 98, 224503 (2018) [3]. R. L. Greene et al., Ann Rev Cond. Matt. Phys. 11, 213 (2020) [4]. T. Sarkar et al., Sci. Adv. 5, eeav6753 (2019) [5]. P. R. Mandal et. al., PNAS 116, 5991 (2019) [6]. N. R. Poniatowski et al., Phys. Rev. B 104, 235138 (2021) [7]. T. Sarkar et al., Science 368, 532 (2020).
  Host David Tanner and Peter Hirschfeld

October 31

  Speaker Qiong Yang (University of Michigan)
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November 2 - SPECIAL SEMINAR

  Speaker Daniel Rhodes, MSE & Physics, University of Wisconsin-Madison
  Title Moving Beyond Graphene and 2D Semiconductors: Superconductivity and Ferroelectricity in Few-Layer Td-MoTe2
  Abstract 2D materials are layered materials that may be readily exfoliated down to a single atomic layer, presenting an opportunity to control electronic states and magnetic ordering noninvasively and efficiently. In this talk, I discuss the materials challenges faced by the 2D community in exploring novel 2D materials beyond graphene and 2D transition metal dichalcogenide semiconductors. The materials challenges are not trivial to solve, and meaningful solutions must include complete control over material synthesis and device fabrication, in combination with contact engineering. After discussing these challenges, I will follow up an example material (Td-MoTe2), whereby solutions to the materials challenges allow us to probe how topology emerges from the bulk down to monolayer thicknesses for Td-MoTe2. We will explore how the influence of an electrostatic gate allows us to identify a unique superconducting state in bilayer Td-MoTe2 and its profound influence even when no change in the chemical potential is made. Our results indicate that superconductivity in bilayer Td-MoTe2 can be completely quenched by an electrostatic gate, and that the superconducting behavior is connected to Fermi surface nesting between electron and hole pockets. Not only, because of the monoclinic crystal structure ferroelectric behavior is established and its effects on superconductivity investigated.
  Host Xiao-Xiao- Zhang

November 7

  Speaker Alexander Balatsky (U. Connecticut)
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  Host Peter Hirschfeld

November 9 - Special Seminar at 2pm in 2260

  Speaker Brian Cowan (Royal Holloway College)
  Title NMR as a probe of many body dynamics and collective excitations
  Abstract Nuclear Magnetic Resonance Techniques are proving to be a especially valuable for probing many modern many body problems from fluctuations in unconventional superconductivity to the fundamental dynamics of quantum fluids at very low temepratures. The talk will review the NMR theory that probes collective behaviors along with modern examples.
  Host Neil Sullivan

November 14

  Speaker Li Fang (UCF)
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  Host Xiao-Xiao Zhang

November 21

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November 28

  Speaker Daniel Weissman (Emory)
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December 5

  Speaker Andriy Nevidomskyy (Rice)
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  Host Peter Hirschfeld

December 12

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Condensed Matter / Biophysics Seminars

Spring 2023

Condensed Matter/Biophysics Seminars Mondays at 4:05pm in 2205 NPB


Committee: Yuxuan Wang, Xiao-Xiao Zhang and Purushottam Dixit


January 9

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January 16

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January 23

  Speaker Rahul Nandkishore (CU-Boulder)
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January 30

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February 6

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February 13

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February 20

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February 27

  Speaker Prof Na Hyun Jo (University of Michigan)
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  Host Yoon Lee

March 6

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March 13

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March 20

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March 27

  Speaker Xiao-Xiao Zhang (UF Physics)
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  Host Yoonseok Lee

April 3

  Speaker BingKan Xue
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  Host Xiaoguang Zhang

April 10

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