Physics & Astronomy Colloquium
3:30 PM, Friday, September 23, 2011
Room 155, Chem-Phys Building
Dr. John Tranquada
Condensed Matter Physics and Materials Science Department
Brookhaven National Laboratory
"Seeing Stripes in High Temperature Superconductors''
More than two decades after the discovery of high-temperature superconductivity,
the nature of the electron-pairing mechanism in the copper-oxide superconductors remains
controversial. An important reason for this is that the strong electron-electron interactions
in these materials invalidate the standard models for electronic structure and transport that
work so well in more conventional conductors. The impact of the strong correlations is exemplified
by the antiferromagnetically-ordered Mott insulator state of the parent cuprates.
Superconductivity is induced by doping charge carriers into the parent insulator.
Neutron scattering studies have shown that antiferromagnetic correlations, characteristic
of the correlated insulator, survive in the superconducting phase. How can insulating
and metallic characters coexist? I will discuss experimental evidence that
the doped charge carriers tend to segregate into stripes that separate
antiferromagnetic domains. While stripe order competes with bulk superconductivity,
quantum-fluctuating stripes appear to underlie the superconducting phase. This experimental
picture provides support for theoretical work suggesting that electronic inhomogeneity
is essential for achieving superconductivity at high temperatures.
Refreshments will be served in CP 179 at 3:15 PM