Superconductivity from the Slater mode: Application to KTaO3 heterostructures

M. R. Norman

doi:10.1103/l9xt-3dw7

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Superconductivity from the Slater mode: Application to KTaO3 heterostructures

M. R. Norman

DOI 10.1103/l9xt-3dw7 · Physical Review B

T1

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Abstract

Superconductivity has been observed for the 2D electron gas (2DEG) at the interface of KTaO3 with other oxides, with a transition temperature about an order of magnitude higher than its 3d cousin SrTiO3. The superconducting transition temperature is strongly dependent on the orientation of the interface. Motivated by this observation, we study pairing due to the exchange of the soft transverse optic phonon mode characteristic of quantum paraelectrics and use the resulting theory to comment on the nature of superconductivity of this 2DEG. We find (1) an orientation dependence consistent with experiment along with an anisotropic gap function, but (2) a BCS coupling constant that is smaller than needed and so must be augmented by contributions from other phonons to be consistent with the observed values of Tc.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
KTaO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	0.05	Pressure not reported	onset
KTaO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	2	Pressure not reported	onset