Fluctuations superconductivity and giant negative magnetoresistance in a gate voltage tuned 2D electron liquid with strong spin-orbit impurity scattering.

We present a quantitative theory of the gate-voltage tuned superconductor-to-insulator transition (SIT) observed experimentally in the 2D electron liquid created in the (111) interface between crystalline SrTiO_3 and LaAlO_3 . Considering two fundamental opposing effects of Cooper-pair fluctuations; the critical conductivity enhancement, known as para-conductivity, and its suppression associated with the loss of unpaired electrons due to Cooper-pairs formation, we employ the standard thermal fluctuations theory, modified to include quantum fluctuations within a novel phenomenological approach. Relying on the quantitative agreement found between our theory and a large body of experimental sheet-resistance data, we conclude that spin-orbit scatterings, via significant enhancement of the interaction between fluctuations, strongly enhance the sheet resistance peak at high fields, and reveal anomalous metallic behavior at low fields, due to mixing of relatively heavy electron bands with a light electron band near a Lifshitz point.