Vanishing Hall Coefficient in the Extreme Quantum Limit in Photocarrier-Doped SrTiO_3

摘要

We explore the extreme quantum limit of photogenerated electrons in quantum paraelectric SrTiO_3. This regime is distinct from conventional semiconductors, due to the large electron effective mass and large dielectric constant. At low temperature, the magnetoresistance and Hall resistivity saturate at a high magnetic field, deviating from conventional behavior. As a result, the Hall coefficient vanishes on the scale of the ratio of the Landau level splitting to the thermal energy, indicating the essential role of lowest Landau level occupancy, as limited by thermal broadening.