arXiv subjects

J. A. Jaszczak

Publications and source records attributed to J. A. Jaszczak.

2 recordsLinked to original sources

arXiv2008

Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer

We have studied temperature dependences of electron transport in graphene and its bilayer and found extremely low electron-phonon scattering rates that set the fundamental limit on possible charge carrier mobilities at room temperature. Our measurements have shown that mobilities significantly higher than 200,000 cm2/Vs are achievable, if extrinsic disorder is eliminated. A sharp (threshold-like) increase in resistivity observed above approximately 200K is unexpected but can qualitatively be understood within a model of a rippled graphene sheet in which scattering occurs on intra-ripple flexural phonons.

cond-mat.mes-hall↗

arXiv2006

Landau Level Splitting in Graphene in High Magnetic Fields

The quantum Hall (QH) effect in two-dimensional (2D) electrons and holes in high quality graphene samples is studied in strong magnetic fields up to 45 T. QH plateaus at filling factors $ν=0,\pm 1,\pm 4$ are discovered at magnetic fields $B>$20 T, indicating the lifting of the four-fold degeneracy of the previously observed QH states at $ν=\pm(|n|+1/2)$, where $n$ is the Landau level index. In particular, the presence of the $ν=0, \pm 1$ QH plateaus indicates that the Landau level at the charge neutral Dirac point splits into four sublevels, lifting sublattice and spin degeneracy. The QH effect at $ν=\pm 4$ is investigated in tilted magnetic field and can be attributed to lifting of the spin-degeneracy of the $n=1$ Landau level.

cond-mat.mes-hall↗