Transverse optical plasmons in layered superconductors

Marel, D. van der; Tsvetkov, A. Yu.

doi:10.1007/bf02548125

Cited by 118 publications

(156 citation statements)

References 17 publications

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“…1c and d. For small values of the bilayer splitting, its nature is similar to that of the transverse plasmon introduced in Ref. [2]. The t ?…”

supporting

confidence: 66%

“…(b) The conductivities are calculated using a microscopic model and the linear response theory. This is the main difference with respect to previous phenomenological approaches [2][3][4]. (c) The microscopic model involves the bilayer-split (bonding and antibonding) bands.…”

mentioning

confidence: 89%

“…Its elements are: (a) the local (intra-bilayer -''bl" and inter-bilayer -''int") fields, current densities, conductivities, and an extension of the multilayer formula of Ref. [2]. (b) The conductivities are calculated using a microscopic model and the linear response theory.…”

mentioning

confidence: 99%

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Temperature dependence of the superconductivity-induced collective mode in the c-axis infrared spectra of bilayer cuprate superconductors

Munzar

Chaloupka

Bernhard³

et al. 2010

Physica C: Superconductivity and its Applications

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The low-temperature spectra of the c-axis infrared conductivity of bilayer high-T c cuprate superconductors (HTCS) exhibit two superconductivity-induced modes [Li Yu et al., Phys. Rev. Lett. 100 (2008) 177004; and references therein]. Both can be understood in terms of a microscopic theory developed recently [J. Chaloupka, C. Bernhard, D. Munzar, Phys. Rev. B 79 (2009) 184513]. Here we summarize the elements of the theory and report on the temperature dependence (TD) of the low-energy mode and of the total optical spectral weight (SW). The calculated TD of the mode is consistent with experiment but the trends of the SW are not.

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“…1c and d. For small values of the bilayer splitting, its nature is similar to that of the transverse plasmon introduced in Ref. [2]. The t ?…”

supporting

confidence: 66%

mentioning

confidence: 89%

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Temperature dependence of the superconductivity-induced collective mode in the c-axis infrared spectra of bilayer cuprate superconductors

Munzar

Chaloupka

Bernhard³

et al. 2010

Physica C: Superconductivity and its Applications

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“…Recently Munzar et al [14] explained phonon anomalies in underdoped YBa 2 Cu 3 O 7−δ (Y-123). The explanation is based on the multilayer model of van der Marel and Tsvetkov [15,16,17], and the assumption of a week (Josephson) coupling between the copper-oxygen planes: it has been assumed that the interlayer conductivities are fairly incoherent in the normal state and dominated by the coherent superfluid contribution in the superconducting state. A bilayer superconductor is thus considered as a superlattice of inter-bilayer and intra-bilayer Josephson junctions -this picture is called the Josephson superlattice model.…”

Section: Introductionmentioning

confidence: 99%

Phonon anomalies in trilayer high-Tc cuprate superconductors

Dubroka

Munzar

2004

Physica C: Superconductivity

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We present an extension of the model proposed recently to account for dramatic changes below T c (anomalies) of some c-axis polarized infrared-active phonons in bilayer cuprate superconductors, that applies to trilayer high-T c compounds. We discuss several types of phonon anomalies that can occur in these systems and demonstrate that our model is capable of explaining the spectral changes occurring upon entering the superconducting state in the trilayer compound Tl 2 Ba 2 Ca 2 Cu 3 O 10 . The low-temperature spectra of this compound obtained by Zetterer and coworkers display an additional broad absorption band, similar to the one observed in underdoped YBa 2 Cu 3 O 7−δ and Bi 2 Sr 2 CaCu 2 O 8 . In addition, three phonon modes are strongly anomalous. We attribute the absorption band to the transverse Josephson plasma resonance, similar to that of the bilayer compounds. The phonon anomalies are shown to result from a modification of the local fields induced by the formation of the resonance. The spectral changes in Tl 2 Ba 2 Ca 2 Cu 3 O 10 are compared with those occurring in Bi 2 Sr 2 Ca 2 Cu 3 O 10 , reported recently by Boris and coworkers.

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“…[3] two of us (DvdM and AAT) calculated the dielectric function for cuprate superconductors with two CuO 2 planes per unit cell, using the Lawrence-Doniach model [2] with alternating coupling constants (the 'multilayer model'). A direct consequence was the presence of a transverse optical plasma mode, polarized perpendicular to the planes for propagation along the planes.…”

mentioning

confidence: 99%

Observation of the Transverse Optical Plasmon inSmLa0.8Sr0.2CuO4−δ
Dulić
¹
,
Pimenov
²
,
Marel
³

et al. 2001
Phys. Rev. Lett.
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We present microwave and infrared measurements on SmLa0.8Sr0.2CuO 4−δ , which are direct evidence for the existence of a transverse optical plasma mode, observed as a peak in the c-axis optical conductivity. This mode appears as a consequence of the existence of two different intrinsic Josephson couplings between the CuO2 layers, one with a Sm2O2 block layer, and the other one with a (La,Sr)2O 2−δ block layer. From the frequencies and the intensities of the collective modes we determine the value of the compressibility of the two dimensional electron fluid in the copper oxygen planes. 74.25.Gz In 1966 A.J. Leggett predicted for superconductors with two bands of charge carriers a collective oscillation corresponding to small fluctuations of the relative phases of the two condensates, briefly indicated as excitons below the superconducting gap [1]. In principle these excitons should be observable with electromagnetic radiation, but in practice the effect on the infrared optical properties of most superconducting materials has been too small to be observable, except for, as we will demonstrate in the present paper, the bi-layer cuprate superconductors. The cuprate high temperature superconductors naturally form weakly coupled stacks of superconducting layers [2]. Some members of this family, e.g. Bi 2 Sr 2 CaCu 2 O 8 , have two superconducting layers per unit cell. These materials are realizations of a two-band superconductor, satisfying the following unique conditions: (i) For polarization of the electric field perpendicular to the conducting planes the metallic screening is very weak due to strong anisotropy of the static and dynamical electrical conductivity. (ii) The dipole selection rules allow optical transitions which resonate at the Josephson exciton energy.In Ref.[3] two of us (DvdM and AAT) calculated the dielectric function for cuprate superconductors with two CuO 2 planes per unit cell, using the Lawrence-Doniach model [2] with alternating coupling constants (the 'multilayer model'). A direct consequence was the presence of a transverse optical plasma mode, polarized perpendicular to the planes for propagation along the planes. Similar to a transverse optical phonon, and in contrast to the transverse Josephson plasma resonance (JPR) in single layer cuprates, this mode is observable as an optically allowed absorption in measurements of the optical conductivity. In Fig. 1 close proximity to the optical phonons it was not possible to separate these electronic collective modes from the optical lattice vibrations [5], which complicates the quantitative analysis of this interesting phenomenon.Both in the two-band exciton model and in the multilayer model the collective modes are oscillations of the relative phase of the two condensates, the inertia of which is due to the finite Josephson coupling between the two condensates. In Ref.[1] the restoring force was provided by the fact, that if δN electrons are added to a plane, the free energy increases with an amount δF = µδN + δN 2 /(2Kn 2 ). Here µ, K, and ...

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Transverse optical plasmons in layered superconductors

Cited by 118 publications

References 17 publications

Temperature dependence of the superconductivity-induced collective mode in the c-axis infrared spectra of bilayer cuprate superconductors

Temperature dependence of the superconductivity-induced collective mode in the c-axis infrared spectra of bilayer cuprate superconductors

Phonon anomalies in trilayer high-Tc cuprate superconductors

Observation of the Transverse Optical Plasmon inSmLa0.8Sr0.2CuO4−δ
Dulić
¹
,
Pimenov
²
,
Marel
³

et al. 2001
Phys. Rev. Lett.
Self Cite
47
5
45
0
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Transverse optical plasmons in layered superconductors

Cited by 118 publications

References 17 publications

Temperature dependence of the superconductivity-induced collective mode in the c-axis infrared spectra of bilayer cuprate superconductors

Temperature dependence of the superconductivity-induced collective mode in the c-axis infrared spectra of bilayer cuprate superconductors

Phonon anomalies in trilayer high-Tc cuprate superconductors

Observation of the Transverse Optical Plasmon inSmLa0.8Sr0.2CuO4−δDulić1, Pimenov2, Marel3 et al. 2001Phys. Rev. Lett.Self Cite475450View full textAdd to dashboardCite

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Observation of the Transverse Optical Plasmon inSmLa0.8Sr0.2CuO4−δ
Dulić
¹
,
Pimenov
²
,
Marel
³

et al. 2001
Phys. Rev. Lett.
Self Cite
47
5
45
0
View full text Add to dashboard Cite