https://doi.org/10.1140/epjb/e2013-31136-y
Regular Article
Layer stacking dependence on thermoelectric properties of massive Dirac fermions in bilayer graphene
School of Physics and Optoelectronic Engineering, Nanjing
University of Information Science and Technology, Nanjing
210044, P.R.
China
a
e-mail: njrma@163.com
Received: 18 December 2012
Received in final form: 6 February 2013
Published online: 22 April 2013
We numerically study the thermoelectric transport in AB- and AA-stacked bilayer graphene in the presence of a strong magnetic field and disorder. In the AB-stacked case, we find that the thermoelectric conductivities display different asymptotic behaviors, depending on the ratio between the temperature and the width of the disorder-broadened Landau levels (LLs), similar to those of monolayer graphene. In the high temperature regime, the transverse thermoelectric conductivity αxy saturates to a universal value 5.54kBe/h at the center of each LL, and displays a linear temperature dependence at low temperatures. The calculated Nernst signal has a peak with a height of the order of kB/e, and the thermopower changes sign at the central LL. We attribute this unique behavior to the coexistence of particle and hole LLs. In the AA-stacked bilayer case, it is found that the thermoelectric transport properties are consistent with the behavior of a band insulator. The obtained results demonstrate the sensitivity of the thermoelectric conductivity to the band gap near the Dirac point.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2013