Transport studies at the Mott transition of the two-dimensional organic metal κ-(BEDT-TTF)2Cu[N(CN)2]Br x Cl1- x

Yasin, S.; Dumm, M.; Salameh, B.; Batail, Patrick; Meźière, Cécile; Dressel, Martin

doi:10.1140/epjb/e2010-10743-2

Cited by 46 publications

(60 citation statements)

References 52 publications

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“…2(a) demonstrates the insulating behavior of both compounds, but also important differences: cooling from room temperature κ-Cl crosses over from a semiconducting phase to a Mott insulator at T M ≈ 40 K and orders antiferromagnetically around T N = 25 K. 29,30 For κ-CN the resistivity continuously In Fig. 3 the frequency-dependent reflectivity and conductivity of κ-Cl is plotted for different temperatures and polarizations using data taken by Faltermeier et al 26 Since the optical properties of κ-(BEDT-TTF) 2 Cu[N-(CN) 2 ]Br x Cl 1−x (0 ≤ x < 1) have been presented and extensively analyzed during the last years, we refer to Refs.…”

Section: Results and Analysismentioning

confidence: 99%

“…The up-shift in spectral weight and the reduced contribution of the conduction electrons below 50 K is rather a consequence of the Mott state than magnetic order. 29,33,41 Tuning the effective correlations U/t by chemical 26,33 and hydrostatic pressure 45 causes spectral weight to shift to lower energies and fill the gap. Although the room-temperature conductivity appears similar for both compounds, the further evolvement is dis- tinct: for κ-Cl it is not possible to extract a power-law behavior σ exc 1 (ω) ∝ ω n over a sufficiently large frequency range for any temperature T < 300 K.…”

Section: Power Lawsmentioning

confidence: 99%

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Power-law dependence of the optical conductivity observed in the quantum spin-liquid compoundκ-(BEDT-TTF)2Cu2(CN)
Elsässer
¹
,
Wu
²
,
Dressel
³

et al. 2012
Phys. Rev. B

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Section: Results and Analysismentioning

confidence: 99%

Section: Power Lawsmentioning

confidence: 99%

Power-law dependence of the optical conductivity observed in the quantum spin-liquid compoundκ-(BEDT-TTF)2Cu2(CN)
Elsässer
¹
,
Wu
²
,
Dressel
³

et al. 2012
Phys. Rev. B

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“…35 For γ = 22-28 mJ/mol K 214,16,53 Equation (1) predicts that A = 0.09-0.14 μ cm/K 2 , which agrees with our measured value to within the known accuracy of the theory. Previous contactful measurements found that A 20 μ cm/K 2 ; 75 such a large value suggests that these measurements may be contaminated by the much larger interlayer resistance. Thus, we conclude that our results represent an accurately calibrated measurement of the in-plane resistivity of κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br.…”

mentioning

confidence: 91%

In-plane superfluid density and microwave conductivity of the organic superconductorκ-(BEDT-TTF)2Cu[N(CN)2]Br: Evidence for
Milbradt
¹
,
Bardin
²
,
Truncik
³

et al. 2013
Phys. Rev. B
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4
46
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We report the in-plane microwave surface impedance of a high-quality single crystal of κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br. In the superconducting state, we find three independent signatures of d-wave pairing: (i) a strong, linear temperature dependence of superfluid density; (ii) deep in the superconducting state the quasiparticle scattering rate ∼ T 3 ; and (iii) no BCS coherence peak is observed in the quasiparticle conductivity. Above T c , the Kadowaki-Woods ratio and the temperature dependence of the in-plane conductivity show that the normal state is a Fermi liquid below 23 K, yet resilient quasiparticles dominate the transport up to 50 K. It has been widely argued that the doped Mott insulator describes the essential physics of the cuprates.1 Similarly, the physics of the κ-(ET) 2 X salts (ET is an abbreviation of BEDT-TTF) appears to be connected to the bandwidth-controlled Mott transition.2 Thus, it is essential to identify and understand the important similarities and differences between these two classes of quasi-two-dimensional superconductor. In both the cuprates and the κ-(ET) 2 X salts, the superconducting critical temperature is only two orders of magnitude smaller than the Fermi temperature; in this sense, both are high-temperature superconductors.A broad consensus that the cuprates are d-wave superconductors was quickly reached.3-6 However, the nature of the pairing state of the κ-(ET) 2 X salts has taken longer to understand due to the lack of a "smoking gun" experiment. 7,8 Early on there was clear evidence for singlet pairing. [9][10][11][12] This, and the low symmetry of the organics, limits the pairing symmetry to be either s-wave (A 1g representation of the D 2h point group) or d-wave (B 2g ).13 Early heat capacity experiments suggested s-wave pairing, 14,15 but more recent low-temperature data point to d-wave pairing. 16 Measurements of the NMR relaxation rate support unconventional pairing. [9][10][11][12] Disorder studies show a reduction in T c with increasing scattering 17,18 but, for larger scattering rates, the suppression of T c is less than expected for non-s-wave superconductors.Attempts to locate the nodes expected in a d-wave superconductor have not yet yielded a simple picture. The in-plane thermal conductivity shows a fourfold angular variation with minima at 45• to the crystal axes, 19 whereas when a magnetic field is rotated in the plane both the heat capacity 20 and the millimeter wave absorption 21 have minima when the field is aligned with the crystal axes. At first sight these results seem contradictory, but both experiments are extremely difficult to interpret 22 and a complicated phase diagram could occur as a function of field strength and temperature. 20,22 Nevertheless, as this has not yet been observed, these measurements have not yet settled the pairing symmetry. There have also been attempts to directly image the gap via scanning tunneling microscopy (STM).23 Some care is needed with the interpretation of these experiments as the coherence peaks, the key feature of ...

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“…The inter-dimer transfer integrals are labeled by t and t , and intra-dimer by t d . (c) The temperature dependence of the in-plane dc resistivity ρ(T) evidences an insulating behavior; the magnetic ordering is seen in the susceptibility χ S (T) [17]. (d) The optical conductivity shows a Mott gap below 500 cm −1 when cooled down to low temperatures [19].…”

Section: Introductionmentioning

confidence: 99%

Magnetic ordering and charge dynamics in κ-(BEDT-TTF)₂Cu[N(CN)₂]Cl

Tomić

Pinterić

Ivek

et al. 2013

J. Phys.: Condens. Matter

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The Mott insulator κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Cl consists of molecular dimers arranged on an anisotropic triangular lattice. At low temperatures a pronounced dielectric anomaly is observed, and eventually a canted antiferromagnetic ground state forms. Optical spectroscopy clearly rules out charge imbalance and the existence of quantum electric dipoles with a dipolar-spin coupling. Here we suggest a novel form of spin-charge coupling where the prominent in-plane dielectric response in κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Cl is explained by short-range discommensurations of the antiferromagnetic phase in the temperature range 30 K < T < 50 K, and by relaxation of charged domain walls in the ferromagnetic structure at lower temperatures.

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Transport studies at the Mott transition of the two-dimensional organic metal κ-(BEDT-TTF)2Cu[N(CN)2]Br x Cl1- x

Cited by 46 publications

References 52 publications

Power-law dependence of the optical conductivity observed in the quantum spin-liquid compoundκ-(BEDT-TTF)2Cu2(CN)
Elsässer
¹
,
Wu
²
,
Dressel
³

et al. 2012
Phys. Rev. B

Power-law dependence of the optical conductivity observed in the quantum spin-liquid compoundκ-(BEDT-TTF)2Cu2(CN)
Elsässer
¹
,
Wu
²
,
Dressel
³

et al. 2012
Phys. Rev. B

In-plane superfluid density and microwave conductivity of the organic superconductorκ-(BEDT-TTF)2Cu[N(CN)2]Br: Evidence for
Milbradt
¹
,
Bardin
²
,
Truncik
³

et al. 2013
Phys. Rev. B
35
4
46
1
View full text Add to dashboard Cite

Magnetic ordering and charge dynamics in κ-(BEDT-TTF)₂Cu[N(CN)₂]Cl

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Transport studies at the Mott transition of the two-dimensional organic metal κ-(BEDT-TTF)2Cu[N(CN)2]Br x Cl1- x

Cited by 46 publications

References 52 publications

Power-law dependence of the optical conductivity observed in the quantum spin-liquid compoundκ-(BEDT-TTF)2Cu2(CN)Elsässer1, Wu2, Dressel3 et al. 2012Phys. Rev. B

Power-law dependence of the optical conductivity observed in the quantum spin-liquid compoundκ-(BEDT-TTF)2Cu2(CN)Elsässer1, Wu2, Dressel3 et al. 2012Phys. Rev. B

In-plane superfluid density and microwave conductivity of the organic superconductorκ-(BEDT-TTF)2Cu[N(CN)2]Br: Evidence forMilbradt1, Bardin2, Truncik3 et al. 2013Phys. Rev. B354461View full textAdd to dashboardCite

Magnetic ordering and charge dynamics in κ-(BEDT-TTF)2Cu[N(CN)2]Cl

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Power-law dependence of the optical conductivity observed in the quantum spin-liquid compoundκ-(BEDT-TTF)2Cu2(CN)
Elsässer
¹
,
Wu
²
,
Dressel
³

et al. 2012
Phys. Rev. B

Power-law dependence of the optical conductivity observed in the quantum spin-liquid compoundκ-(BEDT-TTF)2Cu2(CN)
Elsässer
¹
,
Wu
²
,
Dressel
³

et al. 2012
Phys. Rev. B

In-plane superfluid density and microwave conductivity of the organic superconductorκ-(BEDT-TTF)2Cu[N(CN)2]Br: Evidence for
Milbradt
¹
,
Bardin
²
,
Truncik
³

et al. 2013
Phys. Rev. B
35
4
46
1
View full text Add to dashboard Cite

Magnetic ordering and charge dynamics in κ-(BEDT-TTF)₂Cu[N(CN)₂]Cl