Organic superconductors: The Bechgaard salts and relatives

2015 ◽  
Vol 514 ◽  
pp. 279-289 ◽  
Author(s):  
S.E. Brown
Keyword(s):  
Organic Superconductors ◽  
Bechgaard Salts

scholarly journals Application of superhalogens in the design of organic superconductors

2017 ◽  
Vol 41 (24) ◽  
pp. 14847-14850 ◽  
Author(s):  
Ambrish K. Srivastava ◽  
Abhishek Kumar ◽  
Sugriva N. Tiwari ◽  
Neeraj Misra
Keyword(s):  
Organic Superconductors ◽  
Bechgaard Salts

This study shows that the acceptors of super-electrons in organic superconductors belong to the class of superhalogens and proposes that a new series of salts, (TMTSF)2X, can be realized where X is a superhalogen, which possess similar properties to those of the existing Bechgaard salts. Thus, the concept of superhalogens can be useful in designing potential candidates for organic superconductors.

Electrodynamics of molecular organic superconductors studied by μ SR

2004 ◽  
Vol 114 ◽  
pp. 367-369 ◽  
Author(s):  
F. L. Pratt ◽  
S. J. Blundell ◽  
T. Lancaster ◽  
S. L. Lee ◽  
N. Toyota
Keyword(s):  
Organic Superconductors

ORGANIC SUPERCONDUCTORS - THE ROLE OF UMKLAPP, RETARDATION AND ANISOTROPY

1983 ◽  
Vol 44 (C3) ◽  
pp. C3-983-C3-989 ◽  
Author(s):  
H. Gutfreund ◽  
B. Horovitz ◽  
M. Weger
Keyword(s):  
Organic Superconductors

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.

scholarly journals Evolution of Shape and Volume Fraction of Superconducting Domains with Temperature and Anion Disorder in (TMTSF)2ClO4

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 72
Author(s):  
Kaushal K. Kesharpu ◽  
Vladislav D. Kochev ◽  
Pavel D. Grigoriev
Keyword(s):  
Cooling Rate ◽  
Annealing Time ◽  
Volume Fraction ◽  
Density Wave ◽  
Spin Density Wave ◽  
Finite Size ◽  
Organic Superconductors ◽  
Organic Superconductor ◽  
Sample Length ◽  
Sample Shape

In highly anisotropic organic superconductor (TMTSF)2ClO4, superconducting (SC) phase coexists with metallic and spin-density wave phases in the form of domains. Using the Maxwell-Garnett approximation (MGA), we calculate the volume ratio and estimate the shape of these embedded SC domains from resistivity data at various temperature and anion disorder, controlled by the cooling rate or annealing time of (TMTSF)2ClO4 samples. We found that the variation of cooling rate and of annealing time affect differently the shape of SC domains. In all cases the SC domains have oblate shape, being the shortest along the interlayer z-axis. This contradicts the widely assumed filamentary superconductivity along the z-axis, used to explain the anisotropic superconductivity onset. We show that anisotropic resistivity drop at the SC onset can be described by the analytical MGA theory with anisotropic background resistance, while the anisotropic Tc can be explained by considering a finite size and flat shape of the samples. Due to a flat/needle sample shape, the probability of percolation via SC domains is the highest along the shortest sample dimension (z-axis), and the lowest along the sample length (x-axis). Our theory can be applied to other heterogeneous superconductors, where the size d of SC domains is much larger than the SC coherence length ξ, e.g., cuprates, iron-based or organic superconductors. It is also applicable when the spin/charge-density wave domains are embedded inside a metallic background, or vice versa.

de Haas–van Alphen studies of the organic superconductors α-(ET)2(NH4)Hg(SCN)4and κ-(ET)2Cu(NCS)2[with ET = bis(ethelenedithio)-tetrathiafulvalene]

1992 ◽  
Vol 45 (6) ◽  
pp. 3018-3025 ◽  
Author(s):  
J. Wosnitza ◽  
G. W. Crabtree ◽  
H. H. Wang ◽  
U. Geiser ◽  
J. M. Williams ◽  
...  
Keyword(s):  
Organic Superconductors
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