1. Characteristics of the magnetic depopulation of subbands in very narrow systems
- Author
-
Cheng Wq, Mao Jm, Wang Th, Zhou Jm, Qingzhen Huang, and Du Qh
- Subjects
Physics ,Nonlinear system ,Condensed matter physics ,Field (physics) ,Density of states ,Linearity ,Cutoff ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Electronic band structure ,Magnetic field - Abstract
We present a model for electrons confined in narrow conducting channels by a parabolic well under moderate to high magnetic fields which takes into account a cutoff in the filling of the subbands. Such a cutoff gives rise to energy-separated subbands and a two-dimensional (2D) like subband depopulation, resulting in a relation between sublevel index n and inverse magnetic field B-1 such that in the high-field regime it changes over to the well-known 2D form as expected, and in the moderate field regime it shows pronounced deviation from linearity. This agrees well with the experimental results. The linear region of the n-B-1 experimental plot is believed to arise from the two dimensionality of the system. Calculations show that no resolvable 1D sublevel exists in the 0.5-mu-m-wide wire at very small magnetic fields (including zero field), which agrees qualitatively with the experimental results found in other wires that the Hall resistance, R(H), approaches its classical value B/n(e)e in this region and R(H) = 0 at B = 0, where n(e) is the electron concentration. In this model the linear and nonlinear regions in the experimental n-B-1 plot are used to extract the characteristic frequency omega-0, and the effective 2D electron concentration N(e)2D, respectively.
- Published
- 1992