Temperature and Magnetic Field Enhanced Hall Slope of the Dilute 2D Holes in GaAs in the Ballistic Regime

We report the temperature($T$) and perpendicular magnetic field ($B$) dependence of the Hall resistivity $\rho_{xy}(B)$ of dilute metallic two-dimensional(2D) holes in high mobility GaAs quantum wells over a broad range of temperature(0.02-1.25K). The low $B$ Hall coefficient, $R_H$, is found to be enhanced when $T$ decreases. Strong perpendicular magnetic fields further enhance the slope of $\rho_{xy}(B)$ at all temperatures studied. Coulomb interaction corrections of a Fermi liquid in the ballistic regime ($k_BT>\hbar/\tau$ with $\tau$ being the scattering time) can not explain the enhancement of $\rho_{xy}$ which occurs in the same regime as the anomalous metallic longitudinal conductivity. In particular, although the metallic conductivity in 2D systems has been attributed to electron interactions in a Fermi liquid, these same interactions should reduce, {\it not enhance} the slope of $\rho_{xy}(B)$ as $T$ decreases and/or $B$ increases. Preprint available at cond-mat/0411391.