Superconducting phase tuned sample-specific conductance fluctuations

We have studied sample-specific conductance fluctuations tuned by the phase difference between superconducting boundaries attached to a T-shaped two-dimensional electron gas. In low magnetic fields, oscillations due to phase-conjugated Andreev reflections were observed with an amplitude delta G(qp)similar or equal to 0.10e(2)/h. These oscillations were suppressed by a flux of approximately h/e through the interference region. For larger magnetic fields, superconducting-phase modulated sample-specific conductance fluctuations were found with an amplitude delta Gy(Delta phi)similar or equal to.0.005e(2)/h.