Rick Green, University of Maryland

Jeudi 23 Novembre 2017 à 14h00
Amphi Schützenberger, Esc N
2 ème etage
Low temperature transport and Fermi surface reconstruction in the electron-doped cuprate La2-xCexCuO4
Richard L. Greene
Department of Physics and Center for Nanophysics and Advanced Materials (CNAM), University of Maryland, College Park, USA
The origin of high-Tc superconductivity in the strongly correlated cuprates is still a mystery, 30 years after its discovery. In the hole-doped cuprates a complex pseudogap is found in the underdoped part of the phase diagram and this is believed to be related to the cause of the high-Tc superconductivity. However, in the underdoped electron-doped cuprates only the onset of 2D spin fluctuations is observed at the “pseudogap” onset temperature. A significant advantage of electron-doped cuprates is their low critical field ( 10T), which enables transport experiments to probe the low-temperature (down to 35mK) normal state over the entire phase diagram. These experiments [1-3] give evidence for a Fermi surface reconstruction at a critical doping, a very low temperature linear resistivity (ƿ AT) that occurs over a doping range from optimal doping to the end of the superconducting dome (with A scaling with Tc), and an unexpected quantum critical behavior at the end of the superconducting dome. Similar transport results have been found in some hole-doped cuprates [4, 5]. Since the origin of the high-Tc superconductivity is presumably the same in all the cuprates (both p- and n-types), the properties found in the n-doped cuprates are quite important for the complete understanding of superconductivity in the cuprates. This talk will give an introduction to the properties of the n-type cuprates and then present recent data, primarily transport, which is not currently understood. I may also discuss recent work that shows electron doping to produce superconductivity can be done with oxygen as well as Ce in the cuprates.
[1] P. Armitage, P. Fournier, and R. L. Greene, Rev. Mod. Phys. 82, 2421 (2010).
[2] K. Jin et al., Nature 476, 73 (2011).
[3] N.P.Butch et al., PNAS 109, 8440 (2012).
[4] R. A. Cooper et al., Science 323, 603 (2009).
[5] S. Badoux et al., Nature 531, 210 (2016).
rickg (arobase) umd.edu

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