Gate-tunable Subband Degeneracy in Semiconductor Nanowires

Degeneracy and symmetry have a profound relation in quantum systems. Here, wereport gate-tunable subband degeneracy in PbTe nanowires with a nearlysymmetric cross-sectional shape. The degeneracy is revealed in electrontransport by the absence of a quantized plateau. Utilizing a dual gate design,we can apply an electric field to lift the degeneracy, reflected as emergenceof the plateau. This degeneracy and its tunable lifting were challenging toobserve in previous nanowire experiments, possibly due to disorder. Numericalsimulations can qualitatively capture our observation, shedding light on deviceparameters for future applications.