Electronic structure of CrO2 as deduced from its magneto-optical Kerr spectra

We report a combined experimental-computational investigation of the electronic structure of CrO2. We have measured the magneto-optical Kerr spectra of CrO2 at 10 K and 300 K. At 10 K the Kerr signal is significantly enhanced over that obtained at 300 K. We compare the measured Kerr spectra to first-principles theoretical spectra, which we computed using three different approximations to the exchange-correlation functional, i.e., the local spin-density approximation ~LSDA!, generalized gradient approximation ~GGA!, and LSDA1U . The experimental low-temperature magneto-optical Kerr spectra are best explained by calculations employing the GGA functional. The addition of an on-site Coulomb correlation U does not lead to reasonable Kerr spectra.