Fermi Surface and Pseudogap Evolution in a Cuprate Superconductor
Superconductivity arises from pairing of electrons on the Fermi surface. Professors Jenny Hoffman and Subir Sachdev, with colleagues from Harvard, MIT, Nagoya University, and Northeastern University report in Science that they used Fourier transform STM to map a small-to-large Fermi surface transition in the cuprate superconductor Bi2-yPbySr2-xLaxCuO6+d, demonstrating a quantum critical point near optimal doping at zero field. The researchers showed that superconductivity coexists with the pseudogap on the recovered antinodal Fermi surface above optimal doping. They also demonstrates the nanoscale decoherence effect of the pseudogap, despite the robust magnitude of the superconducting order parameter. Their work suggests the importance of mitigating this decoherence at the nanoscale, to optimize superconductivity.
See: Y. He, Y. Yin, M. Zech, A. Soumyanarayanan, M .M. Yee, T. Williams, M. C. Boyer, K. Chatterjee, W. D. Wise, I. Zeljkovic, T. Kondo, T. Takeuchi, H. Ikuta, P. Mistark, R. S. Markiewicz, A. Bansil, S. Sachdev, E. W. Hudson, J. E. Hoffman, "Fermi Surface and Pseudogap Evolution in a Cuprate Superconductor," Science 344: 6184 (9 May 2014) | DOI: 10.1126/science.1248221.