文档介绍：BREVIA
to such high temperatures. First, graphene devices
allow for very high carrier concentrations (up to
1013 cm−2) with only a single 2D subband oc-
Room-Temperature Quantum Hall cupied, which is essential to fully populate the
lowest LL even in ultra-high B. This is in contrast
Effect in Graphene to traditional 2D systems (for example, GaAs het-
erostructures), which are either depopulated al-
ready in moderate B or exhibit multiple subband
K. S. Novoselov,1 Z. Jiang,2,3 Y. Zhang,2 S. V. Morozov,1 H. L. Stormer,2 U. Zeitler,4 J. C. Maan,4 occupation, leading to the reduction of the ef-
3 2 1
G. S. Boebinger, P. Kim, * A. K. Geim * fective energy gap to values well below ℏoc.
Second, the mobility, m, of Dirac fermions in
he quantum Hall effect (QHE), one ex- (Fig. 1B). The quantization in sxy is exact within an our samples does not change appreciably from
ample of a quantum phenomenon that experimental accuracy ≈%().The liquid-helium to room temperature. It remains at
occurs on a truly macroscopic scale, has survival of the QHE to such high temperatures ≈10,000 cm2 V–1 s–1, which yields a scattering
T −
13
been attracting intense interest since its dis- can be attributed to the large cyclotron gaps, ℏoc, time of t e 10 s so that the high field limit
covery in 1980 (1). The QHE, exclusive to characteristic to Dirac fermions in graphene