Roles of spin fluctuation and frustration in the superconductivity of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>β</mml:mi><mml:mtext>−</mml:mtext><mml:msub><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mtext>BDA-TTP</mml:mtext></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:mi>X</mml:mi></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mrow><mml:mo>(</mml

Ito, Hiroshi; Ishihara, Tetsuo; Tanaka, Hisaaki; Kuroda, Shin Ichi; Suzuki, Takeo; Onari, Seiichiro; Tanaka, Yukio; Yamada, Jun; Kikuchi, Kôichi

doi:10.1103/physrevb.78.172506

Cited by 14 publications

(9 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…26) A similar argument based on the dimer model is also seen in the other half-filling organic conductor. 39) However, the recent density-function theory (DFT) calculations using a generalized-gradient-approximation (GGA) suggested a lower t 0 =t ($ 0:8) than the EH results, 38,40) while the previous DFT calculation gave higher values. 41,42) For t 0 =t $ 0:8 at ambient pressure, the b-axis strain increases the frustration.…”

Section: Discussionmentioning

confidence: 96%

Uniaxial Strain Effects on Mott and Superconducting Transitions in κ-(ET)₂Cu₂(CN)₃

2011

View full text Add to dashboard Cite

We have investigated the anisotropic modulation of a triangular lattice in the spin-liquid Mott insulator -(ET) 2 Cu 2 (CN) 3 exhibiting Mott transition accompanied by superconducting transition. Under uniaxial strain along each crystal axis, the superconducting transition temperature T c plotted against the insulator-metal crossover temperature T IM increases. An increase in the superconducting upper critical field confirms the increase in T c under inplane uniaxial strain. The result is distinct from the abrupt monotonic decrease in T c under hydrostatic pressure, indicating that electron correlation cannot be the primary origin of the enhancement of T c . We discuss uniaxial strain effects on the basis of the quadratic temperature dependence of resistivity and the results of band structure calculation.

show abstract

Section: Discussionmentioning

confidence: 96%

Uniaxial Strain Effects on Mott and Superconducting Transitions in κ-(ET)₂Cu₂(CN)₃

2011

View full text Add to dashboard Cite

show abstract

“…Besides TMTSF, TMTTF, BO, ET, and BETS superconductors, there are other superconductors (Scheme 7, numbers in bracket are the total members of each superconducting family and the highest Tc) of CT salts based on symmetric (BEDSe-TTF [140] and BDA-TTP [141][142][143][144]) and asymmetric donors (ESET-TTF [145], S,S-DMBEDT-TTF [146], meso-DMBEDT-TTF [147,148], DMET [149], DODHT [150], TMET-STF [151], DMET-TSF [152], DIETS [153], EDT-TTF [154], MDT-TTF [155,156], MDT-ST [157,158], MDT-TS [159], MDT-TSF [160][161][162][163], MDSe-TSF [164], DTEDT [165], and DMEDO-TSeF [166,167]). κ-(MDT-TTF)2AuI2 (Tc = 3.5 K) exhibited a Hebel-Slichter coherent peak just below Tc, indicating a BCS-type gap with s-symmetry [156].…”

Section: Superconductors Of Other Electron Donor Moleculesmentioning

confidence: 99%

“…On the other hand, d-wave like superconductivity has been suggested for β-(BDA-TTP)2SbF6 [143,144]. β-(BDA-TTP)2X (X = SbF6, AsF6) exhibited a slight Tc increase at the initial stage of uniaxial strain parallel to the donor stack and interlayer direction while Tc decreased perpendicular to the donor stack [142]. θ- [167].…”

Section: Superconductors Of Other Electron Donor Moleculesmentioning

confidence: 99%

Development and Present Status of Organic Superconductors

Saito¹,

Yoshida²

2012

Superconductors - Materials, Properties and Applications

View full text Add to dashboard Cite

based on the two main requirements for the conductivity, namely, (1) a uniform segregated stacking of the same kind of component molecules, and (2) the fractional CT state (uniform partial CT) of the molecules. Since TTF•TCNQ has a low-dimensional segregated stacking, it showed a metal-insulator (MI) transition (Peierls transition) below about 60 K. For TTF•TCNQ, the Peierls transition occurs by the nesting of the one-dimensional Fermi surface causing lattice distortion associated with the strong electron-phonon interaction and forms charge density wave (CDW). There are also several one-dimensional organic metals which show MI transitions by the formation of spin density wave (SDW) when the periodicity of the SDW coincides with the nesting vector of Fermi surface and no lattice distortion occurs in this case. An increase in the electronic dimensionality is inevitable to prevent the nesting of Fermi surfaces and develop superconductors. Several attempts have been made through "pressure", "heavy atom substitution", or "peripheral addition of alkylchalcogen groups" (Fig. 1). The latter two correspond to the enhancement of the self-assembling ability of the molecules. Appropriate examples taking TTF derivatives are shown in Fig. 1. Based on TMTSF molecules several superconductors under pressure have been prepared with warped one-dimensional Fermi surface since 1980 (a in Fig. 1) [9-14]. In general, the ratio of transfer energies (t// / t ⊥) is larger than 3 for one-dimensional Fermi surface and a closed two-dimensional Fermi surface is formed when t// ≤ 3t ⊥ , where t// and t ⊥ are the transfer energies along the directions of the largest and second largest intermolecular interactions. The BO (BEDO-TTF) molecules afforded stable two-dimensional metals having two-dimensional Fermi surface (b in Fig. 1) owing to the strong self-assembling ability by intermolecular S•••S and hydrogen-bonds [15], and only two superconductors are known since 1990 (Tc ≤ 1.5 K). The substitution of an ethylenedioxy group with an ethylenedithio group (BO → ET (BEDT-TTF)) destabilized the metallic state of BO compounds and provided unstable two-dimensional conductors (c in Fig. 1). Consequently, variety of superconductors and other functional solids have been developed based on twodimensional metals of ET since 1982 (Tc ≤ 13.4 K) [16-20] and its analogues (Tc ≤ 10 K) [21]. Figure 1. Strategy for chemical modification of the TTF molecule to increase (arrows) or decrease (dotted arrow) the electronic dimensionality by the aid of enhancement or suppression of the selfassembling ability of the molecules, respectively [16]. Typical Fermi surfaces of TMTSF (a: (TMTSF)2NbF6), BO (b: (BO)2.4I3), and ET (c: β-(ET)2I3) CT solids are depicted.

show abstract

“…Recently, applying uniaxial strain along the c-axis has given higher T c 5 . Applying the uniaxial compression once increases the T c and takes a maximum before it decreases 6 . It is considered that applying the pressure in the I 3 salt increases the overlap between the upper and lower bands, which gradually changes the character of the system from a strongly correlated half-filled system to a moderately correlated quarter filled system.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of electron correlation due to the molecular dimerization in organic superconductorsβ−(BDA-TTP)2X(X=I3,
Aizawa
¹
,
Kuroki
²
,
Yamada
³

2015
Phys. Rev. B
Self Cite
15
0
9
0
View full text Add to dashboard Cite

We perform a first principles band calculation for quasi-two-dimensional organic superconductors β-(BDA-TTP)2I3 and β-(BDA-TTP)2SbF6. The first principles band structures between the I3 and SbF6 salts are apparently different. We construct a tight-binding model for each material which accurately reproduces the first principles band structure. The obtained transfer energies give the differences such as (i) larger dimerization in the I3 salt than the SbF6 salt, and (ii) different signs and directions of the inter-stacking transfer energies. To decompose the origin of the difference into the dimerization and the inter-stacking transfer energies, we adopt a simplified model by eliminating the dimerization effect and extract the difference caused by the inter-stacking transfer energies. From the analysis using the simplified model, we find that the difference of the band structure comes mainly from the strength of dimerization. To compare the strength of the electron correlation having roots in the band structure, we calculate the physical properties originated from the effect of the electron correlation such as the spin susceptibility applying two particle self-consistent (TPSC) method. We find that the maximum value of the spin susceptibility of the I3 salt is larger than that of the SbF6 salt. Hypothetically decreasing the dimerization within the model of the I3 salt, the spin susceptibility takes almost the same value as that of the SbF6 salt for the same magnitude of the dimerization. We expect that the different ground state between the I3 and SbF6 salt mainly comes from the strength of the dimerization which is apparently masked in the band calculation along a particular k-path.

show abstract

Roles of spin fluctuation and frustration in the superconductivity ofβ−(BDA-TTP)2X(

Cited by 14 publications

References 21 publications

Uniaxial Strain Effects on Mott and Superconducting Transitions in κ-(ET)₂Cu₂(CN)₃

Uniaxial Strain Effects on Mott and Superconducting Transitions in κ-(ET)₂Cu₂(CN)₃

Development and Present Status of Organic Superconductors

Enhancement of electron correlation due to the molecular dimerization in organic superconductorsβ−(BDA-TTP)2X(X=I3,
Aizawa
¹
,
Kuroki
²
,
Yamada
³

2015
Phys. Rev. B
Self Cite
15
0
9
0
View full text Add to dashboard Cite

Contact Info

Product

Resources

About

Roles of spin fluctuation and frustration in the superconductivity ofβ−(BDA-TTP)2X(

Cited by 14 publications

References 21 publications

Uniaxial Strain Effects on Mott and Superconducting Transitions in κ-(ET)2Cu2(CN)3

Uniaxial Strain Effects on Mott and Superconducting Transitions in κ-(ET)2Cu2(CN)3

Development and Present Status of Organic Superconductors

Enhancement of electron correlation due to the molecular dimerization in organic superconductorsβ−(BDA-TTP)2X(X=I3, Aizawa1, Kuroki2, Yamada3 2015Phys. Rev. BSelf Cite15090View full textAdd to dashboardCite

Contact Info

Product

Resources

About

Uniaxial Strain Effects on Mott and Superconducting Transitions in κ-(ET)₂Cu₂(CN)₃

Uniaxial Strain Effects on Mott and Superconducting Transitions in κ-(ET)₂Cu₂(CN)₃

Enhancement of electron correlation due to the molecular dimerization in organic superconductorsβ−(BDA-TTP)2X(X=I3,
Aizawa
¹
,
Kuroki
²
,
Yamada
³

2015
Phys. Rev. B
Self Cite
15
0
9
0
View full text Add to dashboard Cite