Charge fluctuations in the slave fermion representation of the t - J model - evidence for phase separation from loop corrections

We investigate the charge density correlation function in the slave fermion representation of the two-dimensional t - J model using the self-consistent perturbation approach developed for that model by Li et al (1992 Phys. Rev. B 45 5428), which to lowest order in (t, J) gives a diagrammatic equivalent to the usual mean field theory. At the lowest order the equal-time correlation function (interpreted as the holon density correlation function) shows similar features to the results of recent high-temperature series calculations. However the loop corrections, representing scattering of holes by the antiferromagnetic spin fluctuations, lead to a divergent compressibility at low temperatures for low hole dopings and small J/t, which we interpret as indicating a tendency towards phase separation at a temperature .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48875/2/c62504.pd

Spectral and dynamic properties of a 2D Luttinger liquid with current-current interactions

We calculate the Green function, particle-hole susceptibility and Cooper pair susceptibility of a 2D Luttinger liquid that results from an electron gas with long-range current-current interactions. The Haldane bosonization scheme allows this model to be written in terms of boson operators, from which the required fermion operators are constructed. We find weakly decaying power law tails in the spectral function and a Kohn anomaly in the 2kF particle-hole susceptibility, but no divergence in the Cooper amplitude.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48874/2/cm941713.pd

Temperature-scaling behavior of the Hall conductivity for Hg-based superconducting thin films

The Hall conductivities of HgBa_{2}CaCu_{2}O_{6+\delta}and HgBa_{2}Ca_{2}Cu_{3}O_{8+\delta} thin films are investigated for a magnetic field parallel to the c axis. The mixed-state Hall conductivity for these compounds is well described by \sigma_{xy}=C_{1}/H+C_{2}+C_{3}H. The prefactor C_1 shows a temperature dependence of the form C_1 = A(1-t)^n near T_c, where t=T/T_c is the reduced temperature. Contrary to the previous results, C_2 also follows a temperature-scaling behavior similar to that of the coefficient C_1. The observed value of n = 1.8 - 2.3 is comparable to the previously observed values for YBa_{2}Cu_{3}O_{7-\delta} and La_{2-x}Sr_{x}CuO_{4}.Comment: 5 pages, 4 eps figure