Microwave surface impedance of κ-(BEDT-TTF<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Cu(NCS<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>, where BEDT-TTF is bis(ethylenedithio)tetrathiafulva

Achkir, D.; Poirier, M.; Bourbonnais, C.; Quirion, G.; Lenoir, C.; Batail, Patrick; Jérôme, D.

doi:10.1103/physrevb.47.11595

Cited by 62 publications

(30 citation statements)

References 20 publications

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“…In the case of κ-(BEDT-TTF) 2 Cu(NCS) 2 , the origin of the upturn raises the same questions. Surface resistance studies have reported an increase in the microwave conductivity of the system below T c [15]. Compared to YBCO [13] this increase is modest, but its very existence makes it tempting to stretch the analogy with the cuprates and suggest that part of the upturn in κ(T) reported here is due to electrons.…”

mentioning

confidence: 76%

Heat Conduction inκ−(BEDT−TTF)2Cu(NCS)2
Belin
¹
,
Behnia
²
,
Deluzet
³

1998
Phys. Rev. Lett.
98
12
64
2
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The first study of thermal conductivity, κ, in a quasi-two-dimensional organic superconductor of the κ-(BEDT-TTF)2X family reveals features analogous to those already observed in the cuprates. The onset of superconductivity is associated with a sudden increase in κ which can be suppressed by the application of a moderate magnetic field. At low temperatures, a finite linear term -due to a residual electronic contribution-was resolved. The magnitude of this term is close to what is predicted by the theory of transport in unconventional superconductors.The superconductors of κ-(BEDT-TTF) 2 X family [1] share a number of similarities with the high-T c cuprates [2]. Both sets of compounds are quasi-two-dimensional with superconductivity confined to conducting planes sandwiched between insulating layers. The metallic state in both families exhibit common features like low carrier densities, strong electronic correlations and proximity of antiferromagnetic insulating state. While Shubnikov-de Haas experiments [3] have established the existence of a well-defined Fermi surface in the κ-(BEDT-TTF) 2 X family, this metallic state presents some more unconventional properties -like a pseudogap in the electronic density of states in κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br [4]-which have been compared to analagous features in underdoped cuprates [2]. As for the symmetry of the superconducting order parameter, it has yet to become the subject of a consensus as nowadays it is the case in the cuprates. While, early penetration-depth studies on κ-(BEDT-TTF) 2 Cu(NCS) 2 led to conflicting results [5], recent NMR [6] and specific heat [7] studies on κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br provided evidence for the presence of nodes in the superconducting gap.In this letter we present the first study of thermal conductivity in a member of this family. According to our results, heat transport in κ-(BEDT-TTF) 2 Cu(NCS) 2 presents features which have already been detected in YBCO and other high-T c cuprates. Notably, the observation of a residual electronic thermal conductivity at very low temperatures provides strong support for presence of nodes in the superconducting order parameter.We measured the thermal conductivity of five κ-(BEDT-TTF) 2 Cu(NCS) 2 single crystals using a conventional four-probe method. Contacts were realized using silver paint on evaporated gold. The heat current was always applied in the basal (highly-conducting) plane. The temperature gradient was measured with two RuO 2 resistance chips which showed small magnetoresistance and a usable sensitivity up to 15K. The resistive heater and the two thermometers were held by small solenoids of 50 µm manganin wire. In this way, we measured the resistance of the sample and the thermometers with minimal heat loss. For temperatures below 0.25 K, we checked our zero-field results by using another device which was designed for very low temperatures and described elsewhere [8]. Our set-up allowed us to measure, in addition to electrical and thermal conductivities, the thermo-electric power of th...

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mentioning

confidence: 76%

Heat Conduction inκ−(BEDT−TTF)2Cu(NCS)2
Belin
¹
,
Behnia
²
,
Deluzet
³

1998
Phys. Rev. Lett.
98
12
64
2
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“…The symmetry of the superconducting state of -(ET) 2 Cu-(NCS) 2 has been controversially described as normal BCStype by Harshman et al, 573 Klein et al, 574 Lang et al, 575 and Dressel et al, 576 or non-BCS type by Kanoda et al, 577 Uemura et al, 578,579 Achkir et al, 580 and Belin et al, 581 based on the penetration depth, relaxation rate, and tunnel-gap measurements. As early as 1990-1991, Kanoda et al 577 and Uemura et al 578 reported that !ðTÞ evaluated by the susceptibility, mSR, and microwave surface impedance measurements is apparently dependent on temperature (T 1 or T 2 ), suggesting the presence of the anisotropic superconducting gap.…”

Section: Symmetry Of Superconductivity;mentioning

confidence: 99%

Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

Saito¹,

Yoshida²

2007

Bulletin of the Chemical Society of Japan

370

127

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“…Neither the underlying pairing mechanism nor the symmetry of the order parameter has been conclusively established. Although NMR [4,5], specific heat [6] and thermal conductivity [7] measurements all suggest a non-conventional pairing state, results of penetration depth measurements have been inconsistent, with evidence for both conventional [8,9] and non-conventional [10][11][12] behavior. However, none of these penetration depth measurements have been performed over a temperature range (T /T c ) and a precision, comparable to those in the cuprates [13].…”

mentioning

confidence: 99%

Low-Temperature Penetration Depth ofκ−(ET)2Cu[N(CN)2
Carrington
¹
,
Bonalde
²
,
Prozorov
³

et al. 1999
Phys. Rev. Lett.
144
19
122
0
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We present high precision measurements of the penetration depth of single crystals of κ−(ET)2Cu[N(CN)2]Br and κ−(ET)2Cu(NCS)2 at temperatures down to 0.4 K. We find that, at low temperatures, the in-plane penetration depth (λ ) varies as a fractional power law, λ ∼ T 3 2 . Whilst this may be taken as evidence for novel pair excitation processes, we show that the data are also consistent with a quasilinear variation of the superfluid density, as is expected for a d-wave superconductor with impurities or a small residual gap. Our data for the interplane penetration depth show similar features and give a direct measurement of the absolute value, λ ⊥ (0) = 100 ± 20 µm.PACS numbers: 74.70. Kn, 74.25.Nf Compounds of the family κ−(ET) 2 X have the highest transition temperatures of all organic superconductors known to date [1]. They have recently attracted considerable attention because of their similarity to the high T c cuprates and the possibility that they may also have a non-conventional paring state [2]. The two materials studied here, κ−(ET) 2 Cu[N(CN) 2 ]Br (T c ∼ 11.6 K) and κ−(ET) 2 Cu(NCS) 2 (T c ∼ 9.6 K), are highly anisotropic, layered, extreme type II superconductors. As in the cuprates, the superconducting phase in these materials is in close proximity to an antiferromagnetic phase. Both antiferromagnetic spin fluctuations and a pseudogap have been detected in NMR measurements in the normal state [3]. Neither the underlying pairing mechanism nor the symmetry of the order parameter has been conclusively established. Although NMR [4,5], specific heat [6] and thermal conductivity [7] measurements all suggest a non-conventional pairing state, results of penetration depth measurements have been inconsistent, with evidence for both conventional [8,9] and non-conventional [10][11][12] behavior. However, none of these penetration depth measurements have been performed over a temperature range (T /T c ) and a precision, comparable to those in the cuprates [13]. In this Letter, we present measurements of both the in-plane λ , and the interplane, λ ⊥ , penetration depths in κ−(ET) 2 Cu[N(CN) 2 ]Br and κ−(ET) 2 Cu(NCS) 2 at temperatures down to 0.4 K.Our measurements were performed on single crystals of κ−(ET) 2 Cu[N(CN) 2 ]Br and κ−(ET) 2 Cu(NCS) 2 which were grown at Argonne National Laboratory. Details of the growth procedures have been given elsewhere [14]. Penetration depth measurements were performed using a 13 MHz tunnel diode oscillator [15] mounted on a 3 He refrigerator. The low noise level [ ∆F F0 ≃ 10 −9 ], and low drift of the oscillator allows us to obtain high resolution data with a very small temperature spacing interval. The samples were attached, with a small amount of vacuum grease, to a sapphire rod which fitted inside the copper sense coil. The sense coil was calibrated using spheres of Aluminum. The sample temperature was measured with a calibrated Cernox thermometer attached to the other end of the sapphire rod. The samples were cooled slowly (0.1-1.0 K/min) to avoid introducing disorder [1...

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Microwave surface impedance of κ-(BEDT-TTF)2Cu(NCS)2, where BEDT-TTF is bis(ethylenedithio)tetrathiafulva

Cited by 62 publications

References 20 publications

Heat Conduction inκ−(BEDT−TTF)2Cu(NCS)2
Belin
¹
,
Behnia
²
,
Deluzet
³

1998
Phys. Rev. Lett.
98
12
64
2
View full text Add to dashboard Cite

Heat Conduction inκ−(BEDT−TTF)2Cu(NCS)2
Belin
¹
,
Behnia
²
,
Deluzet
³

1998
Phys. Rev. Lett.
98
12
64
2
View full text Add to dashboard Cite

Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

Low-Temperature Penetration Depth ofκ−(ET)2Cu[N(CN)2
Carrington
¹
,
Bonalde
²
,
Prozorov
³

et al. 1999
Phys. Rev. Lett.
144
19
122
0
View full text Add to dashboard Cite

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Microwave surface impedance of κ-(BEDT-TTF)2Cu(NCS)2, where BEDT-TTF is bis(ethylenedithio)tetrathiafulva

Cited by 62 publications

References 20 publications

Heat Conduction inκ−(BEDT−TTF)2Cu(NCS)2Belin1, Behnia2, Deluzet3 1998Phys. Rev. Lett.9812642View full textAdd to dashboardCite

Heat Conduction inκ−(BEDT−TTF)2Cu(NCS)2Belin1, Behnia2, Deluzet3 1998Phys. Rev. Lett.9812642View full textAdd to dashboardCite

Development of Conductive Organic Molecular Assemblies: Organic Metals, Superconductors, and Exotic Functional Materials

Low-Temperature Penetration Depth ofκ−(ET)2Cu[N(CN)2Carrington1, Bonalde2, Prozorov3 et al. 1999Phys. Rev. Lett.144191220View full textAdd to dashboardCite

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Heat Conduction inκ−(BEDT−TTF)2Cu(NCS)2
Belin
¹
,
Behnia
²
,
Deluzet
³

1998
Phys. Rev. Lett.
98
12
64
2
View full text Add to dashboard Cite

Heat Conduction inκ−(BEDT−TTF)2Cu(NCS)2
Belin
¹
,
Behnia
²
,
Deluzet
³

1998
Phys. Rev. Lett.
98
12
64
2
View full text Add to dashboard Cite

Low-Temperature Penetration Depth ofκ−(ET)2Cu[N(CN)2
Carrington
¹
,
Bonalde
²
,
Prozorov
³

et al. 1999
Phys. Rev. Lett.
144
19
122
0
View full text Add to dashboard Cite