Novel angular effect and electron orbital motion in quasi-one-dimensional conductors

We experimentally and theoretically demonstrate a new type of angular effect of magnetoresistance in quasi-one-dimensional (Q1D) conductors, say “the third angular effect”, which follows the “Lebed resonances” and the “Danner-Chaikin oscillations”. This is a kink structure appearing on the angular dependence of the interlayer magnetoresistance when the magnetic field is rotated in the most conducting plane. We report the observation of the third angular effect in a well-established Q1D conductor (TMTSF)2ClO4 in which both of conventional angular effects have been already observed. We numerically show that the third angular effect is deduced from the semiclassical magnetotransport theory in the same way as the two conventional angular effects. We also show that this effect originates from the appearance or vanishing of closed electron orbits on the sheetlike Fermi surface.