Microwave spectroscopy of quasiparticle transport in the (b)over-cap direction of YBa2Cu3O6.993 - art. no. 064509

Measurements of the microwave (b) over cap axis surface impedance of a high quality single crystal of YBa2Cu3O6.993 at five discrete frequencies betwe en 1 and 75 GHz are presented. Despite the complication of the (b) over cap axis oriented chain layer, the underlying behavior of the CuO2 planes rema ins evident. It is demonstrated that the (b) over cap axis microwave conduc tivity can be adequately described by the sum of a Drude term and a frequen cy independent background; the former being attributed to thermally excited quasiparticle transport from quasi-two-dimensional bands and the latter to a broad spectral feature associated with a quasi-one-dimensional band.