We characterize the linear and nonlinear electron transport in quantum point contacts (QPCs) realized by a hybrid combination of etching and gating. We demonstrate that the strong electron confinement generated through this hybrid QPC process results in quantized subbands with a large energy separation, leading to the observation of robust one-dimensional quantum-transport effects. Measurements of the nonlinear differential conductance reveal an unexpected bunching of curves at , rather than at the expected value of . Application of a simple analytical model indicates that this bunching is associated with the highly asymmetric manner in which the source-drain voltage is dropped across the QPC near pinch-off and under nonequilibrium conditions.
Linear and nonlinear conductance of ballistic quantum wires with hybrid confinement
H. Kothari, A. Ramamoorthy, R. Akis, S. M. Goodnick, D. K. Ferry, J. L. Reno, J. P. Bird; Linear and nonlinear conductance of ballistic quantum wires with hybrid confinement. J. Appl. Phys. 1 January 2008; 103 (1): 013701. https://doi.org/10.1063/1.2827466
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