The mid-infrared Hall effect in optimally-doped Bi_2 Sr_2 CaCu_2 O_{8+δ}

Abstract

Heterodyne polarometry is used to measure the frequency dependence in the mid IR from 900 to 1100 cm${}^{-}1$ and temperature dependence from 35 to 330 K of the normal state Hall transport in single crystal, optimally doped Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$. The results show a simple Drude behavior in the Hall conductivity ${\sigma }_{xy}$ which stands in contrast to the more complex, extended Drude behavior for the longitudinal conductivity ${\sigma }_{xx}$. The mid IR Hall scattering rate ${\gamma }_{xy}$ increases linearly with temperature and has a small, positive, projected intercept at T=0. The longitudinal scatter rate, in contrast, is much larger and exhibits very little temperature dependnece. The Hall frequency indicates a carrier mass which is 6.7 times the band mass and which decreases slighly with increasing frequency. These disparate behaviors are consistent with calculations based on the fluctuation-exchange interaction using current vertex corrections.

2 pages, 3 figures