Potassium-tetracyanoquinodimethane (K-TCNQ): A spin-Peierls system

Lépine, Y.; Caillé, A.; Larochelle, V.

doi:10.1103/physrevb.18.3585

Cited by 63 publications

(18 citation statements)

References 34 publications

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“…An SP transition is of the second-order and the transition temperature T p is usually very low, typically lower than 20 K. 23 The phase transitions of M-TCNQ have been regarded as a kind of SP transitions. [24][25][26] Actually, the phase transitions of M-TCNQ are of the first order and their transition temperatures are very high, so that they are not typical SP transitions. To explain the features of the phase transitions of M-TCNQ, the importance of the charge degree of freedom 27 and the structural nature of the transition 19 have been suggested.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast photoinduced melting of spin-Peierls phase in the organic charge-transfer compounds alkali-tetracyanoquinodimethane

et al. 2007

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Photoinduced phase transitions in spin-Peierls ͑SP͒ systems of alkali ͑M =K,Na͒-tetracyanoquinodimethane ͑TCNQ͒ have been studied by a reflection-type femtosecond ͑fs͒ pump-probe spectroscopy. The SP phase is destabilized by the generation of photocarriers through the breaking of the spin-singlet states in dimers. It results in the decrease of the dimeric molecular displacements within a few hundred of femtoseconds over several tens of TCNQ molecules. It is accompanied by the displacive-type coherent oscillations, which consist mainly of three modes with the frequencies of 20, 49, and 90 cm −1 in K-TCNQ and of two modes with the frequencies of 49 and 99 cm −1 in Na-TCNQ. By taking into account the temperature dependence of the Raman scattering spectra, the mode with 20 cm −1 in K-TCNQ and the modes with 49 and 99 cm −1 in Na-TCNQ are assigned to the phonon modes in the SP ground state, while the modes with 49 and 90 cm −1 in K-TCNQ are assigned to the local modes originating from the photoexcited states. Polarization dependence of the Raman scattering signals shows that the 20-cm −1 mode of K-TCNQ and the 49-cm −1 mode of Na-TCNQ are longitudinal optical ͑LO͒ modes, whereas the 99-cm −1 mode of Na-TCNQ is a transverse optical ͑TO͒ mode. Namely, the LO mode plays an important role on the stabilization of the SP phase in K-TCNQ, while both the LO and TO modes in Na-TCNQ. Such a difference is discussed by scrutinizing the difference of the crystal structures and the nature of the SP transitions in the two compounds.

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Section: Introductionmentioning

confidence: 99%

Ultrafast photoinduced melting of spin-Peierls phase in the organic charge-transfer compounds alkali-tetracyanoquinodimethane

et al. 2007

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“…Unfortunately, due to limitations of the equipment it was not possible to get magnetic data on the KTCNQ sample as this would require temperatures in excess of 350 K, which is not easily achievable on the MPMS. However, the magnetic properties of the salt are well documented elsewhere [35], which have been analyzed and can be seen in the Supplemental Material [31]. Using the same model as for the KTCNQF 4 sample, a value of = 1639(71) K was calculated using the data collected by the Faraday method.…”

Section: Fig 2 M/h Vs T For Ktcnqfmentioning

confidence: 99%

Tuneability and criticality in a three-dimensional stacked molecular system

et al. 2016

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“…The magnetic susceptibility decreases rapidly below T, because of the formation of magnetically inactive (singlet) TCNQ dimer. In this sense, the transition is viewed as a spin-Peierls transition (7,8). K-TCNQ investigated here is one such alkaline TCNQ and shows insulating behavior over the whole temperature region below and above T,.…”

mentioning

confidence: 99%

Current-Induced Insulator-Metal Transition and Pattern Formation in an Organic Charge-Transfer Complex

Kumai¹,

Okimoto²,

Tokura

1999

Science

133

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Organic molecular Mott insulators, in which carriers are localized as a result of the electron correlation, showed nonlinear electric conduction upon application of a high electric field along the molecular stacking axis. The current-driven low-resistive state of potassium 7,7,8,8-tetracyanoquinodimethanane was stabilized down to 2 kelvin, where a metallic path was visible with a microscope. The current flow caused a stripe-like periodic phase-segregation into the carrier-rich and carrier-poor regions along the current path.

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Potassium-tetracyanoquinodimethane (K-TCNQ): A spin-Peierls system

Cited by 63 publications

References 34 publications

Ultrafast photoinduced melting of spin-Peierls phase in the organic charge-transfer compounds alkali-tetracyanoquinodimethane

Ultrafast photoinduced melting of spin-Peierls phase in the organic charge-transfer compounds alkali-tetracyanoquinodimethane

Tuneability and criticality in a three-dimensional stacked molecular system

Current-Induced Insulator-Metal Transition and Pattern Formation in an Organic Charge-Transfer Complex

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