Speaker
J P Hill
(Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton NY 11793, USA)
Description
The dynamics of S = ½ quantum spins on a 2D square lattice lie at the heart of the mystery of the cuprates. In bulk cuprates such as La2CuO4, the presence of a weak inter-layer coupling (and other interactions) stabilizes 3D Neel order up to high temperatures. In a truly 2D system however, thermal fluctuations melt long range order at any finite temperature. Here, we utilize Cu L-edge RIXS to measure the spin response of isolated one-unit-cell thick layers of La2CuO4. We show that coherent magnons persist even in a single layer of La2CuO4 despite the loss of magnetic order, with no evidence for resonating valence bond (RVB)-like spin correlations. We also observe a high-energy magnetic continuum in the transverse and longitudinal magnetic response. This high-energy continuum is not well described any existing theories. In contrast, K-edge RIXS is sensitive to two spin-flip processes and we utilize this to measure the two-magnon response, providing further constraints on the spin Hamiltonian.
Work reported here was supported in part by the US DOE under DEAC02-98CH10886 and by the Center for Emergent Superconductivity funded by the US DOE, Office of Basic Energy Sciences.
Please specify poster or talk
Talk
Please specify the session
RIXS
Author
J P Hill
(Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton NY 11793, USA)
