Phase transitions at zero magnetic field in Si/SiGe quantum wells

✍ Scribed by M. D'Iorio; J. Lam; D. Brown; H. Lafontaine

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 114 KB
• Volume: 2
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(98)00159-3

✦ Synopsis

A study of the zero magnetic field metal-insulator transition in SiGe quantum well structures and its associated phase diagram reveals the occurrence of two quantum phase transitions in the insulating regime as a function of temperature and carrier density. This is observed as a rapid fall of the resistivity below 400 mK in the insulating phase, followed below 110 mK with a partial recovery and plateau of the resistivity with temperature. A critical carrier density is associated with each one of these transitions, one being 2.2;10 cm\ and the other being 1.8;10 cm. In this work, we explore the nature of these transitions in terms of collective and single-particle phenomena.