Seminar Announcement
Professor Oleg SushkovUniversity of New South Wales, Sydney"Theory of Incommensurate Magnetic Correlations Across the Insulator-Superconductor Transition in Underdoped La2-xSrxCuO4
The main feature in the elastic neutron scattering of
La2-xSrxCuO4 is the
existence of incommensurate peaks with positions that jump from 45 degrees
to 0 degrees at 5% doping. We show that the spiral state of the
t-t'-t''-J model with realistic parameters describes this data perfectly.
We explain why in the insulator the peak is at 45 degrees while it switches to
0 degrees precisely at the insulator-metal transition.
The calculated positions of
the peaks are in agreement with the data in both phases.
The dc hopping conductivity in the insulating phase is anisotropic because
of the spin spiral. The calculated anisotropy also agrees with
experimental data.
Date: Thursday, January 13, 2005
|