110 research outputs found
Quantum Critical Phase and Lifshitz Transition in an Extended Periodic Anderson Model
We study the quantum phase transition in -electron systems as a quantum
Lifshitz transition driven by selective Mott localization in a realistic
extended Anderson lattice model. Using DMFT, we find that a quantum critical
{\it phase} with anomalous scaling separates a heavy Landau-Fermi
liquid from ordered phase(s). Fermi surface reconstruction occurs via the
interplay between, and penetration of the Green function zeros to the poles,
leading to violation of Luttinger's theorem in the selective-Mott phase . We
show how this naturally leads to scale-invariant responses in transport. Our
work is represents a specific (DMFT) realization of the hidden-FL and FL
theories, and holds promise for study of "strange" metal phases in quantum
matter.Comment: 8 pages,5 figure
Berry phase theory of planar Hall effect in Topological Insulators
Negative longitudinal magnetoresistance, in the presence of an external
magnetic field parallel to the direction of an applied current, has recently
been experimentally verified in Weyl semimetals and topological insulators in
the bulk conduction limit. The appearance of negative longitudinal
magnetoresistance in topological semimetals is understood as an effect of
chiral anomaly, whereas it is not well-defined in topological insulators.
Another intriguing phenomenon, planar Hall effect - appearance of a transverse
voltage in the plane of applied co-planar electric and magnetic fields not
perfectly aligned to each other, a configuration in which the conventional Hall
effect vanishes, has recently been suggested to exist in Weyl semimetals. In
this paper we present a quasi-classical theory of planar Hall effect of a
three-dimensional topological insulator in the bulk conduction limit. Starting
from Boltzmann transport equations we derive the expressions for planar Hall
conductivity and longitudinal magnetoconductivity in topological insulators and
show the important roles played by the orbital magnetic moment for the
appearance of planar Hall effect. Our theoretical results predict specific
experimental signatures for topological insulators that can be directly checked
in experiments.Comment: 18 pages, 3 figure
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