Iwai S, Tanaka S, Fujinuma K, Kishida H, Okamoto H, Tokura Y
Correlated Electron Research Center (CERC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-0046, Japan.
Phys Rev Lett. 2002 Feb 4;88(5):057402. doi: 10.1103/PhysRevLett.88.057402. Epub 2002 Jan 16.
Ultrafast optical switching from an ionic ( I) to a neutral ( N) state in TTF-CA was observed in femtosecond reflection spectroscopy. Charge transfer excitation in the I phase produces N donor ( D0) acceptor ( A0) strings within 2 ps. These initial N states decay with a lifetime of 300 ps at 4 K, but rather multiply leading to macroscopic I-N conversion within 20 ps at 77 K just below the N-I transition temperature T(NI). Near T(NI), we also found the evidence for the coherent motion of the macroscopic N-I domain boundary with a period of 85 ps.
在飞秒反射光谱中观察到TTF-CA中从离子态（I）到中性态（N）的超快光学开关。I相中的电荷转移激发在2皮秒内产生N供体（D0）-受体（A0）链。这些初始N态在4K时以300皮秒的寿命衰减，但在刚好低于N-I转变温度T(NI)的77K时，相当多的N态在20皮秒内导致宏观的I-N转换。在T(NI)附近，我们还发现了宏观N-I畴边界以85皮秒的周期进行相干运动的证据。
