We employ a dual-gated geometry to control the band gap Δ in bilayer graphene and study the temperature dependence of the resistance at the charge neutrality point, RNP (T), from 220 to 1.5 K. Above 5 K, RNP (T) is dominated by two thermally activated processes in different temperature regimes and exhibits exp ( T3 /T ) 1/3 below 5 K. We develop a simple model to account for the experimental observations, which highlights the crucial role of localized states produced by potential fluctuations. The high-temperature conduction is attributed to thermal activation to the mobility edge. The activation energy approaches Δ/2 at large band gap. At intermediate and low temperatures, the dominant conduction mechanisms are nearest-neighbor hopping and variable-range hopping through localized states. Our systematic study provides a coherent understanding of transport in gapped bilayer graphene.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Aug 17 2010|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics