Electric field dependent mobility edge and theory of the breakdown of the integer quantum Hall effect

✍ Scribed by J. Riess

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 757 KB
• Volume: 190
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(93)90197-e

✦ Synopsis

We discuss the microscopic mechanism for the onset of dissipation in a quantum Hall system. Based on general results on the time dependence of the states in a disorder-broadened Landau band in the presence of a macroscopic electric field E, it is found that the mobility edges move from the band center towards the band tails when 161 is increased, in agreement with experiments. Since in real samples, 161 is space dependent, the mobility edges are also space dependent. Dissipation (i.e. breakdown of the quantum Hall effect) sets in at points (x, y), where IE(x, Y)I has the value for which a mobility edge attains the Fermi energy. This value depends on the disorder potential and on the filling factor. Inside a sample, the conductivities depend on IE(x, Y)I and hence on space. We discuss experimental applications, including dissipation in opposite corners of a Hall bar and related breakdown phenomena.