Polarization selectivity of charge localization induced by a 7-fs nearly single-cycle light field in an organic metal

Polarization selectivity of light-field-induced charge localization was investigated in an organic metal α−(BEDT−TTF)2I3 with a triangular lattice. Dependences of transient reflectivity spectra on polarizations of the 7-fs pump and probe lights indicate that a short-range charge order (CO) is induced efficiently from the metallic phase for the pump polarization perpendicular to the 1010-type CO axis. A numerical solution of a time-dependent Schrödinger equation clarified that the 1010 CO is induced by field-induced re-distribution of charges cooperating with competing intersite Coulomb repulsions in the triangular lattice.