Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics

Dressel, Martin; Peterseim, Tobias

doi:10.3390/cryst7010017

Cited by 19 publications

(20 citation statements)

References 135 publications

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“…Especially in low-dimensional system fluctuations as well as electron-electron and electron-phonon interactions play a crucial role, eventually destabilizing the equilibrium state. This picture is similar to the model suggested for the photo-induced phase transition in TTF-CA [56,59].…”

Section: Discussionsupporting

confidence: 73%

“…Following the approach presented in Ref. [28,56], we calculated the temporal behavior of the sample temperature and correlate it with the temperature-dependent sample resistance depicted in Figure 5. The result of the simulation is visualized in Figure 10 for various temperatures T between 125 K and 154 K. We assume that the complete pulse energy is absorbed and transferred into Joule heat at the surface of the specimen as the penetration depth is only a few hundred nanometers.…”

Section: Discussionmentioning

confidence: 99%

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Light-Induced Current Oscillations in the Charge-Ordered State of (TMTTF)2SbF6

Peterseim¹,

Dressel²

2017

Preprint

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Below T CO = 157 K the quasi-one-dimensional charge-transfer salt (TMTTF) 2 SbF 6 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. The findings are discussed and compared to comparable phenomena in other low-dimensional electron systems.

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Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Light-Induced Current Oscillations in the Charge-Ordered State of (TMTTF)2SbF6

Peterseim¹,

Dressel²

2017

Preprint

Self Cite

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show abstract

Section: Discussionsupporting

confidence: 88%

“…Following the approach presented in Ref. [28,70], we calculated the temporal behavior of the sample temperature and correlate it with the temperature-dependent sample resistance depicted in Figure 6. The result of the simulation is visualized in Figure 11 for various temperatures T between 125 K and 154 K. We assume that the complete pulse energy is absorbed and transferred into Joule heat at the surface of the specimen as the penetration depth is only a few hundred nanometers.…”

Section: Discussionmentioning

confidence: 99%

Light-Induced Current Oscillations in the Charge-Ordered State of (TMTTF)2SbF6

Peterseim

Dressel

2017

Crystals

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Below T CO = 157 K the quasi-one-dimensional charge-transfer salt (TMTTF) 2 SbF 6 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.

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“…The evolution of the ionicity in each phase and its jump at the N-I transition was firstly obtained from electronic [5,17] and vibrational [18] optical spectroscopies. This point is extensively reviewed and updated in this NI issue [19,20]. The ionicity q is estimated to be in the range 0.2-0.3 with a slight increase when decreasing temperature in the N phase.…”

Section: Symmetry Analysis and Structural Changes Of Ttf-camentioning

confidence: 99%

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et al. 2017

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Abstract:Although the Neutral-Ionic transition in mixed stack charge-transfer crystals was discovered almost forty years ago, many features of this intriguing phase transition, as well as open questions, remain at the heart of today's science. First of all, there is the most spectacular manifestation of electronic ferroelectricity, in connection with a high degree of covalency between alternating donor and acceptor molecules along stacks. In addition, a charge-transfer instability from a quasi-neutral to a quasi-ionic state takes place concomitantly with the stack dimerization, which breaks the inversion symmetry. Moreover, these systems exhibit exceptional one-dimensional fluctuations, with an enhancement of the effects of electron-lattice interaction. This may lead to original physical pictures for the dynamics of pre-transitional phenomena, as the possibility of a pronounced Peierls-type instability and/or the generation of unconventional non-linear excitations along stacks. Last but not least, these mixed stack charge-transfer systems constitute a valuable test bed to explore some of the key questions of ultrafast photo-induced phenomena, such as multiscale dynamics, selective coherent excitations and non-linear responsiveness. These different aspects will be discussed through the structural and dynamical features of the neutral-ionic transition, considering old and recent results, open questions and future opportunities. In particular, we revisit the structural changes and symmetry considerations, the pressure-temperature phase diagrams and conclude by their interplay with the photo-induced dynamics.

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Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics

Cited by 19 publications

References 135 publications

Light-Induced Current Oscillations in the Charge-Ordered State of (TMTTF)2SbF6

Light-Induced Current Oscillations in the Charge-Ordered State of (TMTTF)2SbF6

Light-Induced Current Oscillations in the Charge-Ordered State of (TMTTF)2SbF6

Back to the Structural and Dynamical Properties of Neutral-Ionic Phase Transitions

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