84 research outputs found
Protocols for characterizing quantum transport through nano-structures
In this work, we have analyzed the exact closed-form solutions for transport
quantities through a mesoscopic region which may be characterized by a
polynomial functional of resonant transmission functions. These are then
utilized to develop considerably improved protocols for parameters relevant for
quantum transport through molecular junctions and quantum dots. The protocols
are shown to be experimentally feasible and should yield the parameters at much
higher resolution than the previously proposed ones.Comment: 5 pages, 2 figure
Interplay between strong correlations and magnetic field in the symmetric periodic Anderson model
Magnetic field effects in Kondo insulators are studied theoretically, using a
local moment approach to the periodic Anderson model within the framework of
dynamical mean-field theory. Our main focus is on field-induced changes in
single-particle dynamics and the associated hybridization gap in the density of
states. Particular emphasis is given to the strongly correlated regime, where
dynamics are found to exhibit universal scaling in terms of a field-dependent
low energy coherence scale. Although the bare applied field is globally
uniform, the effective fields experienced by the conduction electrons and the
-electrons differ because of correlation effects. A continuous
insulator-metal transition is found to occur on increasing the applied field,
closure of the hybridization gap reflecting competition between Zeeman
splitting and screening of the -electron local moments. For intermediate
interaction strengths the hybridization gap depends non-linearly on the applied
field, while in strong coupling its field dependence is found to be linear. For
the classic Kondo insulator YbB, good agreement is found upon direct
comparison of the field evolution of the experimental transport gap with the
theoretical hybridization gap in the density of states.Comment: 8 pages, 8 figure
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