12,929 research outputs found
Two-Dimensional Inversion Asymmetric Topological Insulators in Functionalized III-Bi Bilayers
The search for inversion asymmetric topological insulators (IATIs) persists
as an effect for realizing new topological phenomena. However, so for only a
few IATIs have been discovered and there is no IATI exhibiting a large band gap
exceeding 0.6 eV. Using first-principles calculations, we predict a series of
new IATIs in saturated Group III-Bi bilayers. We show that all these IATIs
preserve extraordinary large bulk band gaps which are well above
room-temperature, allowing for viable applications in room-temperature
spintronic devices. More importantly, most of these systems display large bulk
band gaps that far exceed 0.6 eV and, part of them even are up to ~1 eV, which
are larger than any IATIs ever reported. The nontrivial topological situation
in these systems is confirmed by the identified band inversion of the band
structures and an explicit demonstration of the topological edge states.
Interestingly, the nontrivial band order characteristics are intrinsic to most
of these materials and are not subject to spin-orbit coupling. Owning to their
asymmetric structures, remarkable Rashba spin splitting is produced in both the
valence and conduction bands of these systems. These predictions strongly
revive these new systems as excellent candidates for IATI-based novel
applications.Comment: 17 pages,5figure
Quasi-particle random phase approximation with quasi-particle-vibration coupling: application to the Gamow-Teller response of the superfluid nucleus Sn
We propose a self-consistent quasi-particle random phase approximation (QRPA)
plus quasi-particle-vibration coupling (QPVC) model with Skyrme interactions to
describe the width and the line shape of giant resonances in open-shell nuclei,
in which the effect of superfluidity should be taken into account in both the
ground state and the excited states. We apply the new model to the Gamow-Teller
resonance in the superfluid nucleus Sn, including both the isoscalar
spin-triplet and the isovector spin-singlet pairing interactions. The strength
distribution in Sn is well reproduced and the underlying microscopic
mechanisms, related to QPVC and also to isoscalar pairing, are analyzed in
detail.Comment: 32 pages, 11 figures, 4 table
Topological Crystalline Insulator and Quantum Anomalous Hall States in IV-VI based Monolayers and their Quantum Wells
Different from the two-dimensional (2D) topological insulator, the 2D
topological crystalline insulator (TCI) phase disappears when the mirror
symmetry is broken, e.g., upon placing on a substrate. Here, based on a new
family of 2D TCIs - SnTe and PbTe monolayers - we theoretically predict the
realization of the quantum anomalous Hall effect with Chern number C = 2 even
when the mirror symmetry is broken. Remarkably, we also demonstrate that the
considered materials retain their large-gap topological properties in quantum
well structures obtained by sandwiching the monolayers between NaCl layers. Our
results demonstrate that the TCIs can serve as a seed for observing robust
topologically non-trivial phases.Comment: 5 pages, submitted on 27th Feb 201
Quantum Hall Conductivity in a Landau Type Model with a Realistic Geometry
In this paper, we revisit some quantum mechanical aspects related to the
Quantum Hall Effect. We consider a Landau type model, paying a special
attention to the experimental and geometrical features of Quantum Hall
experiments. The resulting formalism is then used to compute explicitely the
Hall conductivity from a Kubo formula.Comment: LaTeX, 1 eps figur
Agronomic practices influence soil biodiversity with strong feedback to plant growth
Non-Peer Reviewe
Pyrosequencing based analysis of soil bacterial communities under long-term soil tillage and crop residue management in semiarid environments
Non-Peer Reviewe
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