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Evidence for a metal–insulator transition atB = 0 in Si/SiGe/Si quantum wells

✍ Scribed by M. D'iorio; D. Brown; J. Lam; D. Stewart; S. Deblois; H. Lafontaine

Publisher
Elsevier Science
Year
1998
Tongue
English
Weight
71 KB
Volume
23
Category
Article
ISSN
0749-6036

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✦ Synopsis

The temperature dependence of the resistivity of gated Si-SiGe quantum-well structures has revealed a metal-insulator transition as a function of carrier density at zero magnetic field. Although early scaling theories have argued against the existence of a metal-insulator transition at zero temperature in infinite two-dimensional systems, it is now clear experimentally that such a transition can occur in systems with short-range scatterers. We have studied the magneto-transport properties of holes confined in strained p-type Si-Si 0.87 Ge 0.13 -Si quantum wells grown by ultra-high-vacuum chemical-vapor deposition. In the temperature range 25 mK-4.2 K, there is a transition from an insulating phase at low carrier densities to a metallic phase at high carrier densities with a transition boundary near 3.3 × 10 11 cm -2 . Evidence for a Coulomb gap is presented in the insulating phase.

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