Wavelength-resolved study of the photodoping effect in YBa2Cu3Ox

The Hall effect and the resistivity of oxygen-depleted YBa2Cu3Ox were measured insitu during photoexcitation at various photon energies between 1.1 and 2.1 eV, and at several temperatures between 70 K and 290 K. At low temperatures, the photodoping efficiency shows two distinct maxima at about 1.5 eV and 1.85 eV, respectively. The low energy peak dominates the photodoping at 70 K, but rapidly decreases at higher temperatures. The Hall effect measurements indicate that the 1.5-eV peak arises mainly from the enhancement of the carrier mobility. In contrast, the 1.85-eV results from the enhancement of the carrier density.