Eng Kevin, Feng X G, Popović Dragana, Washburn S
National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
Phys Rev Lett. 2002 Apr 1;88(13):136402. doi: 10.1103/PhysRevLett.88.136402. Epub 2002 Mar 15.
The temperature dependence of conductivity sigma(T) of a two-dimensional electron system in silicon has been studied in parallel magnetic fields B. At B = 0, the system displays a metal-insulator transition at a critical electron density n(c)(0), and dsigma/dT>0 in the metallic phase. At low fields ( B < or approximately equal to 2 T), n(c) increases as n(c)(B)-n(c)(0) proportional, variant Bbeta ( beta approximately 1), and the zero-temperature conductivity scales as sigma(n(s),B,T = 0)/sigma(n(s),0,0) = f(B(beta)/delta(n)), where delta(n) = [n(s)-n(c)(0)]/n(c)(0) and n(s) is electron density, as expected for a quantum phase transition. The metallic phase persists in fields of up to 18 T, consistent with the saturation of n(c) at high fields.
在平行磁场B中研究了硅中二维电子系统的电导率σ(T)与温度的关系。在B = 0时，该系统在临界电子密度n(c)(0)处呈现金属-绝缘体转变，且在金属相中dsigma/dT>0。在低场（B≤2 T）下，n(c)随n(c)(B)-n(c)(0)∝Bβ（β≈1）增加，零温度电导率按σ(n(s),B,T = 0)/σ(n(s),0,0) = f(Bβ/δ(n))缩放，其中δ(n) = [n(s)-n(c)(0)]/n(c)(0)且n(s)是电子密度，这是量子相变所预期的。金属相在高达18 T的磁场中持续存在，这与高场下n(c)的饱和一致。
