Mapping Confinement Potential in a Quasi-1D Electron System

We investigate the channel potential profiles in a one-dimensional (1D) electron gas defined by a pair of split-gate and a top gate on the surface of GaAs/AlGaAs heterostructure. It has been observed that at low carrier concentration and weak confinement, the ground state conductance doubles in a 1D wire due to the ground state splitting into two separate rows each contributing 2e²/h [1,2]. Various factors including electron-electron interactions and formation of hybridized ground energy states possibly explain the relaxation in the second dimension. We will show the role of confinement potential in modulating the electrons configuration in the channel by solving Poisson-Schrodinger equations. A correlation between the potential in the channel and the appearance of double row electron configuration at various top and split gate voltage combinations has been studied and compared with the experimental results.

[1] S. Kumar, K. J. Thomas, L. W. Smith, M. Pepper, G. L. Creeth, I. Farrer, D. Ritchie, G. Jones, and J. Griffiths, Phys. Rev. B 90, 201304 (2014).
[2] S. Kumar, M. Pepper, S. N. Holmes, H. Montagu, Y. Gul, D. A. Ritchie, and I. Farrer, Phys. Rev. Lett. 122, 086803 (2019).