An unusual technique utilizing the two-dimensional junction configuration is introduced to study the pairing symmetry of a YBa 2 Cu 3 O 7Ϫy cuprate superconductor. The zero bias conductance peak due to the Andreev bound states was measured for the YBa 2 Cu 3 O 7Ϫy /I/Ag ramp-edge tunnel junctions with different crystalinterface boundary angles fabricated on the same chip. It was found to develop monotonically as the angle was increased and became a maximum at 45°. Two gaplike structures were also found at the intermediate angle of 30°. The result implies that d x2Ϫy2 -wave pairing symmetry predominates in this cuprate. RAPID COMMUNICATIONS PRB 62 R6133 ANGLE-RESOLVED ANDREEV BOUND STATES IN . . . 55, 15 282 ͑1997͒. 29 L.

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