  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.
