Low-energy Charge Dynamics in La 0.7 Ca 0.3 Mno 3 Typeset Using Revt E X

Direct experimental estimations of the low-energy (1.5∼10 meV) complex dielectric constants spectrum and its temperature variation have been investigated for La 0.7 Ca 0.3 MnO 3 thin films using terahertz time-domain spec-troscopy. At low temperatures, a clear Drude-term emerges. With increasing temperature, the scattering rate increases, while the plasma frequency decreases, derived both from a simple Drude model. Finally, a Drude-term submerges well below the insulator-metal transition temperature. Low-energy charge dynamics is discussed on the basis of the present results.