Competing Electronic States in Cuprate Superconductors

TYPECondensed Matter Seminar
Speaker:M. Hücker
Affiliation:Brookhaven National Laboratory
Location:Lidow 724
Remark:Note the special day and time
Abstract:The past year has produced new and exciting evidence for proximity of the superconducting ground state in the cuprates to competing states with static spin and/or charge density modulations. For more than a decade the “direct” observation of these modulated states was limited to two distinct groups of materials and techniques: Spin and charge modulations with a "stripe" pattern were detected only in La-based cuprates, such as La2-x(Ba,Sr)xCuO4, with diffraction techniques. Charge modulations with "checkerboard" or more “nematic” pattern only with scanning tunneling spectroscopy in cuprates amenable to cleaving, most famously in Bi2Sr2CaCu2O8+. In this respect the recent discovery of charge order in YBa2Cu3O6+ with hard and soft X-ray diffraction has been game-changing. I will compare the new findings for YBa2Cu3O6+ [1-3] with recent results for La2-xBaxCuO4 [4-6], and show that these two compounds meet at the crossroad of two fundamentally different approaches of the superconducting phase in the cuprates: Mott and Fermi-liquid physics. Independent of their potentially different origin, the charge ordered states of both compounds compete in a very similar way with bulk superconductivity, as has been revealed by X-ray diffraction in a magnetic field. This makes one wonder if and how they are connected. Understanding their physics seems crucial and, hopefully, will provide important clues about the superconductivity itself.

[1] G. Ghiringhelli et al., Science 337, 821 (2012).
[2] J. Chang et al., Nat. Phys. 8, 871 (2012).
[3] E. Blackburn et al., arXiv 1212.3836.
[4] M. Huecker et al., Phys. Rev. B 87, 014501 (2013).
[5] M. Huecker et al., Phys. Rev. B 83, 104506 (2011).
[6] M. Huecker et al., Phys. Rev. Lett. 104, 057004 (2010).