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Light-Induced Current Oscillations in the Charge-Ordered State of (TMTTF)2SbF6
摘要： Below TCO = 157 K the quasi-one-dimensional charge-transfer salt (TMTTF)2SbF6 undergoes a pronounced phase transition to a charge-ordered ground state. We have explored the non-linear and photoconductive behavior as a function of applied voltage, laser pulse energy and temperature. Besides a decay of the photoconductive signal in a double exponential fashion in the millisecond range, we discover current oscillations in the kHz range induced by the application of short laser pulses. While the resonance frequencies do not depend on voltage or laser intensity and vary only slightly with temperature, the amplitude changes linearly with the laser intensity and voltage. We suggest that photo-induced fluctuations of the charge-ordered state alter the current flow of the single particles and hence, the photocurrent. The findings are discussed and compared to comparable phenomena in other low-dimensional electron systems.
关键词： TMTTF,non-linear transport,calculations of band structure and optical conductivity,charge-transfer salts,photoconductivity,current oscillations,charge-order phase transition
更新于2025-09-11 14:12:44
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Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics
摘要： The neutral-ionic phase transition in TTF-CA was investigated by steady-state and time-resolved infrared spectroscopy. We describe the growth of high-quality single crystals and their characterization. Extended theoretical calculations were performed in order to obtain the band structure, the molecular vibrational modes and the optical spectra along all crystallographic axes. The theoretical results are compared to polarization-dependent infrared reflection experiments. The temperature-dependent optical conductivity is discussed in detail. We study the photo-induced phase transition in the vicinity of thermally-induced neutral-ionic transition. The observed temporal dynamics of the photo-induced states is attributed to the random-walk of neutral-ionic domain walls. We simulate the random-walk annihilation process of domain walls on a one-dimensional chain.
关键词： domain-wall motion,neutral-ionic phase transition,steady-state and transient infrared spectroscopy,TTF-CA,charge-transfer salts,characterization,random-walk simulations,light-induced phase transition,vibrational spectroscopy,crystal growth
更新于2025-09-09 09:28:46