Electron-phonon pairing mechanism: cuprates with high value of the critical temperature

Szczęśniak, R.; Durajski, A. P.

doi:10.48550/arxiv.1206.5531

Cited by 3 publications

(3 citation statements)

References 47 publications

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“…In the case of SiH 4 (H 2 ) 2 under pressure at 270 GPa and Si 2 H 6 at p = 250 GPa, the theoretical results have predicted the existence of the high-temperature superconducting state: T C = 129.83 K and T C = 173.36 K, respectively [17], [18]. We notice that the above values of the critical temperature are even higher than for the cuprates [19].…”

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confidence: 73%

The high-pressure superconductivity in SiH4: the strong-coupling approach

Szczesniak,

Durajski

2013

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In the paper, the thermodynamic parameters of the high-pressure superconducting state in the SiH4 compound have been determined (p = 250 GPa). By using the Eliashberg equations in the mixed representation, the critical temperature, the energy gap, and the electron effective mass have been calculated. It has been stated that the critical temperature (TC ) decreases from 51.65 K to 20.62 K, if the Coulomb pseudopotential increases (µ ⋆ ∈ 0.1, 0.3 ). The dimensionless ratio 2∆ (0) /kBTC decreases from 4.10 to 3.84, where the symbol ∆ (0) denotes the value of the order parameter close to the zero temperature. The ratio of the electron effective mass to the band electron mass is high, and it reaches maximum equal to 1.95 for the critical temperature.

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confidence: 73%

The high-pressure superconductivity in SiH4: the strong-coupling approach

Szczesniak,

Durajski

2013

Preprint

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“…In addition, the other thermodynamic parameters differ very significantly from the predictions of the BCS theory [24]. In particular, the ratio of the energy gap to the critical temperature assumes values comparable to the values observed in the high-temperature superconductors (cuprates) [23], [25], [26].…”

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confidence: 85%

The thermodynamic properties of the high-pressure superconducting state in the hydrogen-rich compounds

Szczȩśniak¹,

Durajski²

2013

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The ab initio calculations suggest that the superconducting state in CaH6 under the pressure (p) at 150 GPa has the highest critical temperature among the examined hydrogen-rich compounds. For this reason, the relevant thermodynamic parameters of the superconducting state in CaH6 have been determined; a wide range of the Coulomb pseudopotential has been assumed: µ ⋆ ∈ 0.1, 0.3 . It has been found that: (i) The critical temperature (TC) changes in the range from 243 K to 180 K. (ii) The values of the ratio of the energy gap to the critical temperature (R∆ ≡ 2∆ (0) /kBTC ) can be found in the range from 5.42 to 5.02. (iii) The ratio of the specific heat jump (∆C (TC )) to the value of the specific heat in the normal state (C N (TC)), which has been represented by the symbol RC , takes the values from 3.30 to 3.18. (iv) The ratio RH ≡ TCC N (TC) /H 2 C (0), where HC (0) denotes the critical thermodynamic field, changes from 0.122 to 0.125. The above results mean that even for the strong electron depairing correlations the superconducting state in CaH6 is characterized by a very high value of TC, and the remaining thermodynamic parameters significantly deviate from the predictions of the BCS theory. The study has brought out the expressions that correctly predict the values of the thermodynamic parameters for the superconducting state in CaH6 and for the compounds: SiH4 (H2) 2 , Si2H6, B2H6, SiH4, GeH4, and PtH. Next, in the whole family of the hydrogen-rich compounds, the possible ranges of the values have been determined for TC, R∆, RC , and RH. It has been found that the maximum value of the critical temperature can be equal to 764 K, which very well correlates with TC for metallic hydrogen (p = 2 TPa). Other parameters (R∆, RC , and RH ) should not deviate from the predictions of the BCS theory more than the analogous parameters for CaH6.

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“…For the considered pressure, the low temperature energy * Electronic address: szczesni@wip.pcz.pl gap at the Fermi surface (2∆ (0)) is so large that the dimensionless ratio 2∆ (0) /k B T C equals approximately 6 [15]. The comparable value of 2∆ (0) is only observed in the group of the high-temperature superconductors (cuprates) [16], [17].…”

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confidence: 97%

Study of the superconducting state in the Cmmm phase of GeH4 compound

Szczęśniak,

Durajski,

Szczęśniak

2012

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The superconducting state, that gets induced in the GeH4 compound under the pressure at 20 GPa, is characterized by the high critical temperature TC (µ ⋆ ) ∈ 54.5, 31.2 K, where µ ⋆ is the Coulomb pseudopotential, and µ ⋆ ∈ 0.1, 0.3 . Other thermodynamic parameters for the considered range of the Coulomb pseudopotential significantly differ from the predictions of the BCS model. In particular: (i) the ratio of the energy gap to the critical temperature (R∆ ≡ 2∆ (0) /kBTC ) changes from 4.07 to 3.88; (ii) the value of the parameter RC ≡ ∆C (TC ) /C N (TC ) decreases from 1.85 to 1.69, where ∆C denotes the specific heat jump, and C N is the specific heat of the normal state; (iii) the ratio RH ≡ TC C N (TC ) /H 2 C (0) increases from 0.147 to 0.155; HC represents the thermodynamic critical field.

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Electron-phonon pairing mechanism: cuprates with high value of the critical temperature

Cited by 3 publications

References 47 publications

The high-pressure superconductivity in SiH4: the strong-coupling approach

The high-pressure superconductivity in SiH4: the strong-coupling approach

The thermodynamic properties of the high-pressure superconducting state in the hydrogen-rich compounds

Study of the superconducting state in the Cmmm phase of GeH4 compound

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