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 the session
RIXS
Please specify poster or talk
Talk
Primary author
J P Hill
(Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton NY 11793, USA)
