Study of the superconducting phase in silicene under biaxial tensile strain

Abstract

The electron-doped silicene under the influence of the biaxial tensile strain is predicted to be the phonon-mediated superconductor. By using the Eliashberg formalism, we investigate the thermodynamic properties of the superconducting silicene in the case when the tension is 5% and the electron doping equals 3.5 × 10 14 cm −2 . Under such conditions, silicene monolayer is expected to exhibit the highest superconducting transition temperature (TC ). In particular, based on the electron-phonon spectral function and assuming wide range of the Coulomb pseudopotential values (µ ∈ 0.1, 0.3 ) it is stated that the superconducting transition temperature decreases from 18.7 K to 11.6 K. Similar behavior is observed in the case of the zeroth temperature superconducting energy gap at the Fermi level: 2∆(0) ∈ 6.68, 3.88 meV. Other thermodynamic parameters differ from the predictions of the Bardeen-Cooper-Schrieffer theory. In particular, the ratio of the energy gap to the critical temperature changes in the range from 4.14 to 3.87. The ratio of the specific heat jump to the specific heat in the normal state takes the values from 2.19 to 2.05, and the ratio of the critical temperature and specific heat in the normal state to the thermodynamic critical field increases from 0.143 to 0.155. It is also determined that the maximum value of the electron effective mass equals 2.11 of the electron band mass.

Thermodynamic Properties of the Superconducting State in Metallic Hydrogen: Electronic Correlations, Non-conventional Electron-Phonon Couplings and the Anharmonic Effects

“…It is worth noticing that the value of T C drops down while compression increases. A similar effect we found also in the H 3 S hydrogenated compound [29]. Interestingly, our results with respect to the value of T C for this compound seem to harmonize relatively well with the maximum values of the critical temperature experimentally measured for H 3 S or also LaH 10 , reported to be [T C ] H 3 S = 203 K [22] and [T C ] LaH 10 = 215 K [32] (or else [T C ] LaH 10 = 260 K [33]).…”

“…The superconducting state in the system of compressed hydrogen and sulphur is induced by the electron-phonon interactions. Thermodynamic properties of the considered phase can be successfully described using the Eliashberg formalism and the density functional theory (DFT) [26][27][28][29][30][31].…”

Silicene: Recent theoretical advances

“…19 A biaxial strain is also found to lead to superconductivity. 28 A uniaxial strain is expected to lead to a gap opening due to the symmetry lowering and this was initially reported. 20,29 However, more recent density functional theory (DFT) calculations 21,22 did not obtain a gap and interpreted the disagreement to insufficient number of k points near the crossing in the earlier works.…”

Electron-phonon properties, structural stability, and superconductivity of doped antimonene

“…Computational studies predicting the superconductivity in monolayer graphene [28,29] and phosphorene [30] were preceding the experimental observations [18,20,21]. Also, superconductivity at nonzero charge doping has already been predicted for recently proposed arsenene [31] (monolayer As), as well as for silicene [32]. Experimental data on superconductivity of these materials are not available yet.…”