Two types of breakdown of quantum Hall effect depending on the electron density fluctuation

✍ Scribed by K. Oto; T. Sanuki; S. Takaoka; K. Murase; K. Gamo

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 157 KB
• Volume: 12
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(01)00269-7

✦ Synopsis

We investigate di erent types of the breakdown of the quantum Hall e ect (QHE), which are characterized by the sample width dependence of the critical current for the breakdown. The distinction of two di erent types of breakdown is thought to be the properties of the two-dimensional electron gas (2DEG) wafers, but it is not related directly to the 2DEG mobility and electron density determined by Hall measurement at low magnetic ÿeld. We observe the switching between linear and sublinear dependence of the QHE breakdown by varying temperature, gate voltage, and by illumination condition. The type of QHE breakdown is determined by the extent of potential uctuations in the 2DEG, which are characterized by the random potential from ionized donors and by screening e ects, comparing with those resulting from the thermal broadening of the electron distribution. The result of magnetocapacitance between 2DEG and Schottky gate also suggests that the 2DEG homogeneity play an important role in the breakdown of the QHE.