English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We report the observation of a metal-insulator transition (MIT) in a two-dimensional electron gas (2DEG) in a Si/SiGe heterostructure at zero magneticfield. On going through the MIT we observe the corresponding evolution of themagnetic field induced transition between the insulating phase and the quantumHall (QH) liquid state in the QH regime. Similar to the previous reports for aGaAs sample, we find that the critical magnetic field needed to produce thetransition becomes zero at the critical electron density corresponding to thezero field MIT. The temperature dependence of the conductivity in ametallic-like state at zero field is compared with the theory of theinteraction corrections at intermediate and ballistic regimes$k_{B}T\tau/\hbar\geq1$. The theory yields a good fit for the linear part ofthe curve. However the slope of that part of $\sigma_{xx}(T)$ is about twotimes smaller than that reported in other 2D systems with similar values of$r_s$. At the same time, the recent theory of magnetoresistance due toelectron-electron interaction in the case of arbitrary $k_{B}T\tau/\hbar$,smooth disorder and classically strong fields does not seem to be quiteadequate for the description of the parabolic magnetoresistance observed in oursamples. We attribute these results to the fact that neither of these theoriesdeals with the whole scattering potential in a sample but leaves either itslong range or its short range component out of consideration.Comment: 8 pages, 5 figure

physical review. b, condensed matter

Conductivity of a two-dimensional electron gas in a Si/SiGe heterostructure near the metal-insulator transition: Role of the short- and long-range scattering potential