2,509 research outputs found
Compressibility of Interacting Electrons in Bilayer Graphene
Using the renormalized-ring-diagram approximation, we study the
compressibility of the interacting electrons in bilayer graphene. The
compressibility is equivalent to the spin susceptibility apart from a constant
factor. The chemical potential and the compressibility of the electrons can be
significantly altered by an energy gap (tunable by external gate voltages)
between the valence and conduction bands. For zero gap and a typical finite gap
in the experiments, we show both systems are stable.Comment: 5 pages, 6 figure
Absence of broken inversion symmetry phase of electrons in bilayer graphene under charge density fluctuations
On a lattice model, we study the possibility of existence of gapped broken
inversion symmetry phase (GBISP) of electrons with long-range Coulomb
interaction in bilayer graphene using both self-consistent Hartree-Fock
approximation (SCHFA) and the renormalized-ring-diagram approximation (RRDA).
RRDA takes into account the charge-density fluctuations beyond the mean field.
While GBISP at low temperature and low carrier concentration is predicted by
SCHFA, we show here the state can be destroyed by the charge-density
fluctuations. We also present a numerical algorithm for calculating the
self-energy of electrons with the singular long-range Coulomb interaction on
the lattice model.Comment: 8 pages, 6 figure
Study of two-dimensional electron systems in the renormalized-ring-diagram approximation
With a super-high-efficient numerical algorithm, we are able to
self-consistently calculate the Green's function in the
renormalized-ring-diagram approximation for a two-dimensional electron system
with long-range Coulomb interactions. The obtained ground-state energy is found
to be in excellent agreement with that of the Monte Carlo simulation. The
numerical results of the self-energy, the effective mass, the distribution
function, and the renormalization factor of the Green's function for the
coupling constants in the range are also presented.Comment: 4 pages, 5 figure
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