Ultrafast melting of charge ordering in LuFe 2 O 4 probed by terahertz spectroscopy

Ultrafast terahertz response of charge ordering (CO) in LuFe2O4 was investigated by near-infrared-pump (1.55eV) and terahertz-probe (2–9meV) spectroscopy. Photoinduced absorption observed immediately (1ps) after the photoexcitation was attributed to photoinduced melting of the CO. The charge dynamics thereafter can be characterized by subsequent development of the photoinduced conductivity in the low-energy region (2–3meV), implying the formation of a metallic state.