SPIN CONDUCTIVITY AND SPIN-CHARGE SEPARATION IN THE HIGH-T-C CUPRATES

We address the question of how to experimentally test spin-charge sepa ration in the high-T-c cuprates. We demonstrate that a comparison betw een the temperature dependences of the electrical resistivity and spin resistivity can be used for this purpose. Given the known linear in t emperature dependence of the electrical resistivity, the spin resistiv ity should also be Linear in temperature in the absence of spin-charge separation and under conditions appropriate for the optimally doped c uprates, but is in general not so in the presence of spin-charge separ ation. We demonstrate the quantitative feasibility of applying the spi n-injection technique to measure the electron-spin diffusion constant.