Previous abstract
Next abstract
Session Q10 - HTSC: THEORY OF OBSERVATION OF ORDER PRAMETER SYMETRY
Mixed session, Friday morning, March 24, 8:00
Ballroom A4, San Jose Convention Center
Recent measurements Rev. Lett. 72, 2267 (1994) of Josephson currents through a YBa _2 Cu _3 O _7 /Pb Josephson junction have been taken as evidence that the order parameter in YBa _2 Cu _3 O _7 cannot have d_x^2-y^2 symmetry. We will discuss two possible mechanisms by which a nonzero current may be consistent with a d-wave order parameter. First we consider the role that the CuO chains play in breaking the tetragonal symmetry of the system. Second, we consider the contribution to the current made by fourth order tunneling processes. These processes do not vanish for a d-wave/s-wave junction. We will make quantitative comparisons with experimental results for both mechanisms.