scholarly journals Electrodynamics of Bechgaard Salts: Optical Properties of One-Dimensional Metals

2012 ◽  
Vol 2012 ◽  
pp. 1-21 ◽  
Author(s):  
Martin Dressel
Keyword(s):  
Collective Mode ◽  
Density Wave ◽  
Spin Density Wave ◽  
Low Frequency ◽  
Current Status ◽  
Excitation Spectra ◽  
Bechgaard Salts ◽  
One Dimensional ◽  
Open Questions ◽  
Liquid Behavior

The electrodynamic properties of the quasi-one-dimensional organic conductors (TMTSF)2X are discussed, with particular emphasis on important deviations from the simple Drude model, the transition from a Luttinger-liquid to a Fermi-liquid behavior at the dimensional crossover when pressure is applied or temperature reduced, indications of a pseudogap as well as a low-frequency collective mode. Superconductivity and spin-density-wave ground states breaking the symmetry and gaps should occur in the excitation spectra. The previous literature is summarized and the current status of our understanding presented. Novel THz experiments on (TMTSF)2PF6 and (TMTSF)2ClO4 not only shine light into some of the open questions, but also pose new ones.

Low frequency dielectric response in spin density wave phase of bechgaard salts

1999 ◽  
Vol 103 (1-3) ◽  
pp. 2052-2053
Author(s):  
N. Biškup ◽  
T. Vuletić ◽  
D. Herman ◽  
S. Tomić ◽  
M. Nagasawa ◽  
...  
Keyword(s):  
Spin Density ◽  
Dielectric Response ◽  
Density Wave ◽  
Spin Density Wave ◽  
Low Frequency ◽  
Bechgaard Salts ◽  
Wave Phase

MAGNETIC FIELD-INDUCED DENSITY WAVE TRANSITION IN A τ-PHASE ORGANIC CONDUCTOR

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3105-3108 ◽  
Author(s):  
D. GRAF ◽  
L. BALICAS ◽  
J. S. BROOKS ◽  
C. MIELKE ◽  
G. C. PAPAVASSILIOU
Keyword(s):  
Magnetic Fields ◽  
Density Wave ◽  
Spin Density Wave ◽  
Threshold Field ◽  
Pulsed Magnetic Fields ◽  
Abrupt Increase ◽  
Bechgaard Salts ◽  
One Dimensional ◽  
Shubnikov De Haas Oscillations ◽  
Increasing Temperature

Pulsed magnetic fields to 53 tesla reveal a new high field phase transition in τ-[ P-(S,S) - DMEDT-TTF ]2 ( AuBr 2)( AuBr 2) y (where y ~.75). This transition appears as an abrupt increase in the magnetoresistance at a threshold field ( B Th ~44 tesla for T = 0.55 K). B Th shifts toward higher magnetic fields with increasing temperature, and there is evidence of higher field sub-phases. Measurements of Shubnikov de Haas oscillations below 33 tesla have provided compelling evidence as to the two-dimensional (2D), metallic nature of this compound. In the following report we discuss this new unexpected state, reminiscent of the field-induced spin density wave (FISDW) behavior in the quasi one-dimensional (Q1D) Bechgaard salts.

scholarly journals Old Donors for New Molecular Conductors: Combining TMTSF and BEDT-TTF with Anionic (TaF6)1−x/(PF6)x Alloys

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 386
Author(s):  
Magali Allain ◽  
Cécile Mézière ◽  
Pascale Auban-Senzier ◽  
Narcis Avarvari
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Density Wave ◽  
Spin Density Wave ◽  
Orthorhombic Phase ◽  
Molecular Conductors ◽  
Bechgaard Salts ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Resistivity Measurements

Tetramethyl-tetraselenafulvalene (TMTSF) and bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) are flagship precursors in the field of molecular (super)conductors. The electrocrystallization of these donors in the presence of (n-Bu4N)TaF6 or mixtures of (n-Bu4N)TaF6 and (n-Bu4N)PF6 provided Bechgaard salts formulated as (TMTSF)2(TaF6)0.84(PF6)0.16, (TMTSF)2(TaF6)0.56(PF6)0.44, (TMTSF)2(TaF6)0.44(PF6)0.56 and (TMTSF)2(TaF6)0.12(PF6)0.88, together with the monoclinic and orthorhombic phases δm-(BEDT-TTF)2(TaF6)0.94(PF6)0.06 and δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57, respectively. The use of BEDT-TTF and a mixture of (n-Bu4N)TaF6/TaF5 afforded the 1:1 phase (BEDT-TTF)2(TaF6)2·CH2Cl2. The precise Ta/P ratio in the alloys has been determined by an accurate single crystal X-ray data analysis and was corroborated with solution 19F NMR measurements. In the previously unknown crystalline phase (BEDT-TTF)2(TaF6)2·CH2Cl2 the donors organize in dimers interacting laterally yet no organic-inorganic segregation is observed. Single crystal resistivity measurements on the TMTSF based materials show typical behavior of the Bechgaard phases with room temperature conductivity σ ≈ 100 S/cm and localization below 12 K indicative of a spin density wave transition. The orthorhombic phase δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57 is semiconducting with the room temperature conductivity estimated to be σ ≈ 0.16–0.5 S/cm while the compound (BEDT-TTF)2(TaF6)2·CH2Cl2 is also a semiconductor, yet with a much lower room temperature conductivity value of 0.001 to 0.0025 S/cm, in agreement with the +1 oxidation state and strong dimerization of the donors.

Tuning of Spin Density Wave Strengths in Quasi-One-Dimensional Halogen-Bridged NiIIIComplexes with Strong Electron Correlations, [NiIII(chxn)2X]Y2

1999 ◽  
Vol 38 (8) ◽  
pp. 1894-1899 ◽  
Author(s):  
Masahiro Yamashita ◽  
Toshio Manabe ◽  
Kazuo Inoue ◽  
Takuya Kawashima ◽  
Hiroshi Okamoto ◽  
...  
Keyword(s):  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Electron Correlations ◽  
Strong Electron ◽  
One Dimensional ◽  
Strong Electron Correlations

Spin density wave – metal (superconductor) competition: A phase segregation scenario

2002 ◽  
Vol 12 (9) ◽  
pp. 61-64
Author(s):  
C. Pasquier ◽  
M. Héritier ◽  
D. Jérome
Keyword(s):  
Free Energy ◽  
Dispersion Relation ◽  
Fermi Level ◽  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Phase Segregation ◽  
Organic Conductor ◽  
One Dimensional ◽  
Unique Parameter

We present a model comparing the free energy of a phase exhibiting a segregation between spin density wave (SDW) and metallic domains (eventually superconducting domains) and the free energy of homogeneous phases which explains the findings observed recently in (TMTSF)2PF6. The dispersion relation of this quasi-one-dimensional organic conductor is linearized around the Fermi level. Deviations from perfect nesting which stabilizes the SDW state are described by a unique parameter t$'_b$, this parameter can be the pressure as well.

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