1996/01/18 by P. Prelovsek, J. Jaklic
Physics and Astronomy · #cond-mat
published as J. Korean Phys. Soc. 29, 63 (1996) · 7 pages with 5 Postscript figures, RevTeX and epsf required. Presented on the Pacific Conference on Condensed Matter Physics "Complex Materials and Strong Correlation" in Seoul, December 1995
arxiv created 1996/01/18 · arxiv updated 2009/11/30
Recent results for the finite-temperature static and dynamical properties of the planar t-J model, obtained by a novel numerical method for small correlated systems, are reviewed. Of particular interest are T>0 charge and spin response functions: optical conductivity σ(ω) and spin susceptibility χ( q,ω), which show very universal features at intermediate doping. In spin dynamics the universality is best seen in the local spin correlation function, which appears to be T-independent and only weakly doping dependent. Results apply directly to the inelastic neutron scattering and to the NMR relaxation experiments in cuprates. Analysing σ(ω) we find that the current correlation function C(ω) is nearly T- and moreover ω-independent in the regime T <J, leading to the σ(ω) behavior, very close to the marginal Fermi liquid concept and experiments. These properties are interpreted in connection with the large entropy, related to the large degeneracy of the low-lying states and quantum frustration in the doped antiferromagnets. On the other hand, results for the uniform susceptibility χ0(T), as well as for the σ(ω), reveal qualitative changes on entering the underdoped regime.