5,828 research outputs found
Topological states and quantized current in helical molecules
We report a theoretical study of electron transport along helical molecules
under an external electric field, which is perpendicular to the helix axis of
the molecule. Our results reveal that the topological states could appear in
single-helical molecule and double-stranded DNA in the presence of the
perpendicular electric field. And these topological states guarantee adiabatic
charge pumping across the helical molecules by rotating the electric field in
the transverse plane and the pumped current at zero bias voltage is quantized.
In addition, the quantized current constitutes multiple plateaus by scanning
the Fermi energy as well as the bias voltage, and hold for various model
parameters, since they are topologically protected against perturbations. These
results could motivate further experimental and theoretical studies in the
electron transport through helical molecules, and pave the way to detect
topological states and quantized current in the biological systems.Comment: 5 pages, 5 figure
Topological responses from chiral anomaly in multi-Weyl semimetals
Multi-Weyl semimetals are a kind of topological phase of matter with discrete
Weyl nodes characterized by multiple monopole charges, in which the chiral
anomaly, the anomalous nonconservation of an axial current, occurs in the
presence of electric and magnetic fields. Electronic transport properties
related to the chiral anomaly in the presence of both electromagnetic fields
and axial electromagnetic fields in multi-Weyl semimetals are systematically
studied. It has been found that the anomalous Hall conductivity has a
modification linear in the axial vector potential from inhomogeneous strains.
The axial electric field leads to an axial Hall current that is proportional to
the distance of Weyl nodes in momentum space. This axial current may generate
chirality accumulation of Weyl fermions through delicately engineering the
axial electromagnetic fields even in the absence of external electromagnetic
fields. Therefore, this work provides a nonmagnetic mechanism of generation of
chirality accumulation in Weyl semimetals and might shed new light on the
application of Weyl semimetals in the emerging field of valleytronics.Comment: 13 pages, 2 tables, 2 figures, accepted by Physical Review
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