4,511 research outputs found
Comment on "Fock-Darwin States of Dirac Electrons in Graphene-Based Artificial Atoms"
Chen, Apalkov, and Chakraborty (Phys. Rev. Lett. 98, 186803 (2007)) have
computed Fock-Darwin levels of a graphene dot by including only basis states
with energies larger than or equal to zero. We show that their results violate
the Hellman-Feynman theorem. A correct treatment must include both positive and
negative energy basis states. Additional basis states lead to new energy levels
in the optical spectrum and anticrossings between optical transition lines.Comment: 1 page, 1 figure, accepted for publication in PR
Two-component theory of a droplet of electrons in half-filled Landau level
We have investigated low energy excitations of a disk of electrons in
half-filled Landau level using trail wave function and small-size exact
diagonalization approaches. We have constructed a set of many-body basis states
that describe correctly the low energy excitations. In this theory a droplet
consists of two types of composite fermion liquids, and suggests that a droplet
can support an edge magnetoplasmon and low energy droplet excitations. A
possibility of measuring these excitations in a quantum dot is discussed.Comment: Figure1 is available from the authors upon request. Three eps files
are attached to the tex fil
Edge and bulk merons in double quantum dots with spontaneous interlayer phase coherence
We have investigated nucleation of merons in double quantum dots when a
lateral distortion with a reflection symmetry is present in the confinement
potential. We find that merons can nucleate both inside and at the edge of the
dots. In addition to these merons, our results show that electron density
modulations can be also present inside the dots. An edge meron appears to have
approximately a half integer winding number.Comment: 5 pages, 4 figures, Proceedings of 17th International Conference on
High Magnetic Fields in Semiconductor Physic
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