Temperature dependence of superconducting gap of heavy fermion system

Rout, G. C.; Das, Salila

doi:10.1016/s0921-4534(00)00317-8

Cited by 4 publications

(7 citation statements)

References 13 publications

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“…According to the hybridized Hamiltonian [26] that consisted of conduction electron and -electron band, BCS-like pairing band, and hybridization term, we have…”

Section: Model and Calculationmentioning

confidence: 99%

“…= + is the intra-atomic Coulomb interaction between other-electron. The Hamiltonian is linearised by [26]'s technique; then we get the simplified two-bandhybridized Hamiltonian. We can write the Hamiltonian as…”

Section: Model and Calculationmentioning

confidence: 99%

“…Since Moskalenko [1,2] Suhl et al [3] introduced the twoband model that accounts for multiple energy bands in the vicinity of the Fermi energy contributing electron pairing in superconductor, the two-band model has been applied to high temperature superconductor in copper oxides [4][5][6][7][8][9][10], MgB 2 superconductor [11][12][13], and heavy Fermion superconductor [14,15]. Dolgov et al [16] studied the thermodynamic properties of the two-band superconductor: MgB 2 .…”

Section: Introductionmentioning

confidence: 99%

“…The tightbinding band in 2D square lattice and nesting vector = ( , ) was used in their calculations. Rout and Das [26] applied the periodic Anderson model (PAM) for calculating the nonmagnetic ground state of heavy Fermion superconductor. The Hamiltonian of the heavy Fermion systems composed of conduction electron band, -electron band, the hybridization of conduction electron and -electron band, BCS-like pairing band, and the intra-atomic Coulomb interaction of -electron.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we modified the hybridized Hamiltonian of Rout and Das [26] to be the two-band superconductor with hybridization. Some physical properties of two-band hybridized superconductor, that is, critical temperature, zerotemperature order parameter, gap-to-ratio, and isotope effect coefficient, were investigated.…”

Section: Introductionmentioning

confidence: 99%

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The Study on Hybridized Two-Band Superconductor

Chanpoom

Seechumsang

Chantrapakajee

et al. 2013

Advances in Condensed Matter Physics

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The two-band hybridized superconductor which the pairing occurred by conduction electron band and other-electron band are considered within a mean-field approximation. The critical temperature, zero-temperature order parameter, gap-to-Tcratio, and isotope effect coefficient are derived. We find that the hybridization coefficient shows a little effect on the superconductor that conduction electron band has the same energy as other-electron band but shows more effect on the superconductor that conduction electron band coexists with lower-energy other-electron band. The critical temperature is decreased as the hybridization coefficient increases. The higher value of hybridization coefficient, lower value of gap-to-Tcratio, and higher value of isotope effect coefficient are found.

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“…According to the hybridized Hamiltonian [26] that consisted of conduction electron and -electron band, BCS-like pairing band, and hybridization term, we have…”

Section: Model and Calculationmentioning

confidence: 99%

Section: Model and Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Study on Hybridized Two-Band Superconductor

Chanpoom

Seechumsang

Chantrapakajee

et al. 2013

Advances in Condensed Matter Physics

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Superconducting gap anomaly in heavy fermion systems

Rout

Ojha²,

Behera³

2008

Pramana - J Phys

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The heavy fermion system (HFS) is described by the periodic Anderson model (PAM), treating the Coulomb correlation between the f -electrons in the meanfield Hartree-Fock approximation. Superconductivity is introduced by a BCS-type pairing term among the conduction electrons. Within this approximation the equation for the superconducting gap is derived, which depends on the effective position of the energy level of the f -electrons relative to the Fermi level. The latter in turn depends on the occupation probability n f of the f -electrons. The gap equation is solved self-consistently with the equation for n f ; and their temperature dependences are studied for different positions of the bare f -electron energy level, with respect to the Fermi level. The dependence of the superconducting gap on the hybridization leads to a re-entrant behaviour with increasing strength. The induced pairing between the f -electrons and the pairing of mixed conduction and f -electrons due to hybridization are also determined. The temperature dependence of the hybridization parameter, which characterizes the number of electrons with mixed character and represents the number of heavy electrons is studied. This number is shown to be small. The quasi-particle density of states (DOS) shows the existence of a pseudo-gap due to superconductivity and the signature of a hybridization gap at the Fermi level. For the choice of the model parameters, the DOS shows that the HFS is a metal and undergoes a transition to the gap-less superconducting state.

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Microscopic Study of Two Band Superconductivity in Magnesium Diboride Superconductor (MgB<sub>2</sub>)

Sahoo¹,

Mishra²,

Das³

et al. 2021

AJPA

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We formulate a Model Hamiltonian of two band superconductivity for Magnesium Diboride superconductors (MgB 2 ). It is a conventional BCS type metallic superconductor which has the highest critical temperature T c =39K. It is assumed that the superconductivity in MgB 2 arises due to metallic nature of the 2D sheets. From band structure calculations, it is observed that two types of bands i.e. σ and π bands are located at Fermi surface. Here, we consider phonon mediated superconductivity in which σ band is dominant over π band i.e. σ band is more coupled to a superconductor with much higher coupling. We consider a model Hamiltonian with mean field approach and solve this by calculating equations of motion of Green functions for a single particle. We determine the quasi-particle energy from the poles of the Green functions. We derive the single particle correlation functions and determine the two SC order parameters for both σ and π band. Here, the two SC order parameters for the bands are solved self-consistently and numerically. The conduction bandwidth (W) is considered as W=8t 0 , where t 0 is the hopping integral. To make all the physical quantities dimensionless, we divide 2t 0 in each of the physical quantities. We then calculate the gap ratio 2∆(0)/K B T c for both the bands. It is seen form our theoretical model that the two bands of MgB 2 superconductors have two different SC gaps with the same critical temperature. We also observe the variation of dispersion curves of quasi-particles for different temperature parameters for both σ and π band.

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Temperature dependence of superconducting gap of heavy fermion system

Cited by 4 publications

References 13 publications

The Study on Hybridized Two-Band Superconductor

The Study on Hybridized Two-Band Superconductor

Superconducting gap anomaly in heavy fermion systems

Microscopic Study of Two Band Superconductivity in Magnesium Diboride Superconductor (MgB<sub>2</sub>)

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Temperature dependence of superconducting gap of heavy fermion system

Cited by 4 publications

References 13 publications

The Study on Hybridized Two-Band Superconductor

The Study on Hybridized Two-Band Superconductor

Superconducting gap anomaly in heavy fermion systems

Microscopic Study of Two Band Superconductivity in Magnesium Diboride Superconductor (MgB&lt;sub&gt;2&lt;/sub&gt;)

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Microscopic Study of Two Band Superconductivity in Magnesium Diboride Superconductor (MgB<sub>2</sub>)