Magnetic-field-induced breakdown of quasi-one-dimensional quantum-wire quantization

Photoluminescence studies of ${\ln }_{0.13}$${\mathrm{Ga}}_{0.87}$As/GaAsmodulated -barrier quantum wires have been performed with varying orientations. By using high optical excitation, emission from three quantum wire subbands is observed. For fields perpendicular to the wires we observe a distinct transformation of the quantization from quasi-one-dimensional quantum-wire states at low fields to fully quantized quasi-zero-dimensional states at higher fields. This change occurs as the Landau orbit sizes for the several subbands decrease compared to the lateral quantum-wire dimension. The experimental results are consistent with numerical calculations for these quantum wires in magnetic fields.