Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 12: HL Poster I
HL 12.49: Poster
Montag, 1. April 2019, 17:30–20:00, Poster E
Time-dependent photo-conductivity in DCNQI radical ion salts — •Lisa Schraut-May1, Sebastian Hammer1, Florian Hüwe1, and Jens Pflaum1,2 — 1Experimental Physics VI, Julius Maximilian University, 97074 Würzburg — 2ZAE Bayern, 97074 Würzburg
The material class of organic radical anion salts offers a wide range of attractive electronic and photo-physical properties. For instance, dicyanochinondiimine (DCNQI) coordinated by metal atoms is characterized by a low-dimensional metallic ground state at high temperatures which is transferred to an insulating state upon cooling to cryogenic temperatures. The corresponding metal-insulator Peierls transition is tunable by the chemical composition of the Me(DCNQI)2 side-groups and the choosen metal as well as by external parameters, e.g. the hydrostatic pressure. Moreover, it has been demonstrated that the Peierls transition can be initiated by photon absorption on picosecond time scales [1] which renders Me(DCNQI)2 a model system for studying the time-dependent photo-switching between metallic and insulating ground state. We present studies on the transient photo-conductivity in Cu(DCNQI)2 and Li(DCNQI)2 single crystals. We characterize the photo-induced Peierls transition as function of sample temperature, incident light intensity as well as excitation wavelength. The variation of these parameters provides detailed insights in the mechanisms governing the phase transition and allows for evaluation of this material class for application as ultra-fast photo-switches.
[1] F. Karutz et al., Phys. Rev. Lett. 81 (1998) 143