Dμdn in suspended bilayer graphene: The interplay of disorder and band gap

We present an interpretation of recent experimental measurements of dμ/dn in suspended bilayer graphene samples. We demonstrate that the data may be quantitatively described by assuming a spatially varying interlayer potential asymmetry (which generates a band gap) induced by local electric fields resulting from charged-impurity disorder in the graphene environment. We demonstrate that the fluctuations in the interlayer potential asymmetry and density vary between different samples, and that the potential asymmetry fluctuations increase in magnitude as the density fluctuations increase. This indicates that the mechanism causing this effect is likely to be extrinsic. We also provide predictions for the optical conductivity and mobility of suspended bilayer graphene samples with small band gaps in the presence of disorder.