Periodic-orbit resonance in the quasi-one-dimensional organic superconductor „TMTSF...2ClO4

We report the observation of periodic-orbit resonance POR in a metal possessing pure quasi-onedimensional Q1D Fermiology—namely, the organic linear-chain compound TMTSF 2ClO4, whose Fermi surface consists of a pair of weakly warped sheets. The POR phenomenon is related to weak interchain coupling, which allows electrons constrained on open trajectories to acquire small transverse velocities. The application of an appropriately oriented magnetic field induces periodic motion transverse to the chain direction and, hence, to a resonance in the ac conductivity. This resonance phenomenon is closely related to cyclotron resonance observed in metals with closed Fermi surfaces. For the Q1D POR, the field orientation dependence of the resonance is related simply to the Fermi velocity and lattice periodicity.