Superconducting dome in doped 2D superconductors with broken inversion symmetry

Abstract

We analyze an unconventional inter-subband paired phase in a 2D doped superconductor considering both systems with the inversion symmetry and with the inversion symmetry broken. We find that for a centro-symmetric system the inter-subband pairing can appear in the high concentration regime when the repulsive Coulomb interaction leads to the nearly degenerate symmetric and antisymmetric state. We discuss in detail the mutual competition between the intra-and inter-subband paired phase. For systems with broken inversion symmetry, we find that the critical temperature has a characteristic domelike shape as a function of the asymmetry parameter, which is explained as resulting form the inter-subbband pairing. This results is discussed in the context of the domelike shape of Tc in the LaAlO3/SrTiO3 interface.

Impact of spin-orbit interaction on the phase diagram and anisotropy of the in-plane critical magnetic field at the superconducting LaAlO3/SrTiO3 interface

“…Up to date, a few theoretical proposals have been made to explain the characteristic shape of T c . Scenarios that are being considered emphasise the role of electron-electron correlations 2,4 , the strong pair-breaking effect resulting from an interband repulsive interaction 42,43 as well as the intersubband pairing in multiband models 44,45 . Most of them, however, do not reproduce the experimental data with sufficient agreement.…”

Superconducting dome in LaAlO3/SrTiO3 interfaces as a direct consequence of the extended s -wave symmetry of the gap

“…It has been well established that LAO/STO exhibits gate tunable superconductivity with the dome-like shape of T C as a function of gate voltage [1][2][3][4][5][6][7] . The origin of such behavior still remains unclear and is the subject of an ongoing debate [8][9][10][11] , which mainly concentrates around the role of electronic correlations 4,12 , multiband effects 13,14 , and spin-orbit interaction 2,[15][16][17][18] .…”

Interplay between singlet and triplet pairings in multi-band two-dimensional oxide superconductors

“…It is well known that LAO/STO 2DEGs host an unconventional superconducting regime, achievable by tuning the applied gate voltage. The origin of the superconductivity is still not understood [3][4][5][6], and various open questions remain unsolved about the role of quantum electronic correlations [7,8], of multiband effects [9][10][11][12], and of the spin-orbit coupling [13][14][15][16][17]. Moreover, the possibility of topological superconductivity is also under debate [18][19][20][21][22][23].…”