We report first principles calculations of the superconducting properties of fcc potassium under high pres- sure. Using a completely ab initio method we predict a superconducting phase transition at 18 GPa. A maxi- mum critical temperature of about 2 K is observed around 23 GPa, the pressure at which the crossover between the fcc phase and the KIII structure experimentally occurs. At higher pressure, when the fcc phase is experi- mentally unstable, we find, in the phononically stable range, values of T c up to 11 K. In order to understand the underlying mechanisms inducing superconductivity in potassium, we study the effect of pressure on the electronic and vibrational properties, showing a progressive phonon softening near the K point of the Brillouin zone and a concomitant enhancement of the electron-phonon coupling constant ␭. Interestingly, we find that the pressure induced s-d charge transfer causes an increasing anisotropy of the superconducting gap ⌬. Al- though similar to dense Li in many respects, K displays interesting peculiar features.

SANNA, A., FRANCHINI, C., Floris A, PROFETA, G., Lathiotakis NN, Luders M, et al. (2006). Ab-initio prediction of pressure-induced superconductivity in potassium. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 73(14), 1-7 [10.1103/PhysRevB.73.144512].

Ab-initio prediction of pressure-induced superconductivity in potassium

FRANCHINI, CESARE
Membro del Collaboration Group
;
2006

Abstract

We report first principles calculations of the superconducting properties of fcc potassium under high pres- sure. Using a completely ab initio method we predict a superconducting phase transition at 18 GPa. A maxi- mum critical temperature of about 2 K is observed around 23 GPa, the pressure at which the crossover between the fcc phase and the KIII structure experimentally occurs. At higher pressure, when the fcc phase is experi- mentally unstable, we find, in the phononically stable range, values of T c up to 11 K. In order to understand the underlying mechanisms inducing superconductivity in potassium, we study the effect of pressure on the electronic and vibrational properties, showing a progressive phonon softening near the K point of the Brillouin zone and a concomitant enhancement of the electron-phonon coupling constant ␭. Interestingly, we find that the pressure induced s-d charge transfer causes an increasing anisotropy of the superconducting gap ⌬. Al- though similar to dense Li in many respects, K displays interesting peculiar features.
2006
SANNA, A., FRANCHINI, C., Floris A, PROFETA, G., Lathiotakis NN, Luders M, et al. (2006). Ab-initio prediction of pressure-induced superconductivity in potassium. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 73(14), 1-7 [10.1103/PhysRevB.73.144512].
SANNA, ANTONIO; FRANCHINI, CESARE; Floris A; PROFETA, GIANNI; Lathiotakis NN; Luders M; Marques MAL; Gross EKU; Continenza A; Massidda S.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/727320
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