  More than half a century after first being proposed by Sir Nevill Mott, the
deceptively simple question of whether the interaction-driven electronic
metal-insulator transition may be continuous remains enigmatic. Recent
experiments on two-dimensional materials suggest that when the insulator is a
quantum spin liquid, lack of magnetic long-range order on the insulating side
may cause the transition to be continuous, or only very weakly first order.
Motivated by this, we study a half-filled extended Hubbard model on a
triangular lattice strip geometry. We argue, through use of large-scale
numerical simulations and analytical bosonization, that this model harbors a
continuous (Kosterlitz-Thouless-like) quantum phase transition between a metal
and a gapless spin liquid characterized by a spinon Fermi surface, i.e., a
"spinon metal." These results may provide a rare insight into the development
of Mott criticality in strongly interacting two-dimensional materials and
represent one of the first numerical demonstrations of a Mott insulating
quantum spin liquid phase in a genuinely electronic microscopic model.
