2 research outputs found
Conductance anomaly near the Lifshitz transition in strained bilayer graphene
Strain qualitatively changes the low-energy band structure of bilayer
graphene, leading to the appearance of a pair of low-energy Dirac cones near
each corner of the Brillouin zone, and a Lifshitz transition, (a saddle point
in the dispersion relation) at an energy proportional to the strain [M.
Mucha-Kruczynski, I.L. Aleiner, and V.I. Fal'ko, Phys. Rev. B 84, 041404
(2011)]. Here, we show that in the vicinity of the Lifshitz transition the
conductance of a ballistic n-p and n-p-n junction exhibits an anomaly: a
non-monotonic temperature and chemical potential dependence, with the size
depending on the crystallographic orientation of the principal axis of the
strain tensor. This effect is characteristic for junctions between regions of
different polarity (n-p and n-p-n junctions), while there is no anomaly in
junctions between regions of the same polarity (n-n' and n-n'-n junctions).Comment: 10 pages, 4 figures;
http://link.aps.org/doi/10.1103/PhysRevB.85.16542
Transport signatures of pseudomagnetic Landau levels in strained graphene ribbons
In inhomogeneously strained graphene, low-energy electrons experience a valley-antisymmetric pseudomagnetic field which leads to the formation of localized states at the edge between the valence and conduction bands, understood in terms of peculiar n=0 pseudomagnetic Landau levels. Here we show that such states can manifest themselves as an isolated quadruplet of low-energy conductance resonances in a suspended stretched graphene ribbon, where clamping by the metallic contacts results in a strong inhomogeneity of strain near the ribbon ends