Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1811.12303

Floquet Spectrum and Two-Terminal Conductance of a Transition Metal Dichalcogenide Ribbon under a Circularly Polarized Laser Field

A. Huamán·Gonzalo Usaj
View original source ↗Read source document ↗Export metadata ↓

Abstract

We study the transport properties of a monolayer transition metal dichalcogenide (TMDC) ribbon subject to a time periodic circularly polarized laser field. First, we calculate the quasienergy spectrum within the framework of the Floquet theory and analyze the nontrivial topology of the Floquet bulk gaps. The later is revealed by the presence of chiral edge states inside the bulk gaps in finite samples, in agreement with the calculation of the appropriate winding numbers as a function of both the energy and the amplitude of the laser field. The effect of the time dependent perturbation on the equilibrium edge states is also analyzed. Finally, we calculate the two-terminal conductance and discuss how the above mentioned effects manifest on it. In particular, besides the expected suppression of the bulk conductance and the emergence of edge transport at the Floquet gaps, we find that there is an asymmetry between left and right transmission coefficients (in the zigzag case), leading to pumping effects. In addition, we found that the laser field can lead to a complete switch off of the linear conductance when the later is dominated by the equilibrium edge states.

Explore related subjects

cond-mat.mes-hall

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A. Huamán, Gonzalo Usaj. 2018-11-29. Floquet Spectrum and Two-Terminal Conductance of a Transition Metal Dichalcogenide Ribbon under a Circularly Polarized Laser Field. https://doi.org/10.1103/physrevb.99.075423

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Benzo-bis(imidazole) self-assembled monolayers molecular junctions in meta or para conformation: effects of protonation on the electrical and thermal conductances

We report the thermal conductances of molecular junctions made of self-assembled monolayers of benzo-bis(imidazole) molecules, without side groups or functionalized with two phenylamine side groups. In the two cases, when the molecules are connected to the electrodes by thiol anchoring groups in the meta-position, the thermal conductance is decreased compared to the same molecules connected in the para-position (ca. 16-29 nW/K and ca. 37-40 nW/K, respectively) in agreement with the theoretically predicted phonon interference effect in molecular junctions. Upon protonation, the thermal conductances of the meta-connected molecular junction increase by about 50% (reversible behavior upon deprotonation). The fact that only the thermal conductance of the meta-connected molecular junction is sensitive to the protonation/deprotonation is tentatively related to modifications of the structural organization of the molecules in the monolayer, which modifies the thermal conductance at the molecule/electrode interfaces. The electrical conductance is lower for the meta-connected molecule than for the para-connected one, due to destructive quantum interferences, as expected and reported for other molecular junctions. The conductance further decreases (reversibly) upon protonation. The energy position of the molecular orbital involved in the electron transport is not modified by the protonation and the decrease in current is related to changes in the molecule organization in the monolayer, which modulate the electronic coupling energy at the molecule/electrode interfaces.

cond-mat.mes-hall↗
arXiv2026

Hydrodynamics of two-dimensional electrons due to scattering by disorder

The hydrodynamic regime of electron transport, induced by fast inter-electron collisions, was discovered in high-quality nanostructures in recent ten years. However, signs of hydrodynamic transport, primarily, the giant negative magnetoresistance, were observed even at very low temperatures, when electron-electron scattering is too weak to affect the transport. To address this puzzle, here we develop a theory of mixed, hydrodynamic and non-Markovian, magnetotransport of two-dimensional electrons at zero temperature in samples with weak but still important disorder. Namely, we account for both the memory effects at electron scattering by localized defects in magnetic field and an unconventional viscosity effect due to electron scattering by defects in bulk and by rough sample edges. Solution of the model yields a strong negative magnetoresistance, which exhibits at zero magnetic field a sharp maximum in narrower samples or a blunt maximum in wider samples. This and other our results explain various properties of the giant negative magnetoresistance observed on ultra-high-quality GaAs quantum wells, thereby we apparently reveal the nature of low-temperature magnetotransport in these systems.

cond-mat.mes-hall↗
arXiv2026

Symplectic Hopf Insulator: Delicate Topology in Bosonic Bogoliubov-de Gennes Systems

Recent advances in topological phases have highlighted the role of symplectic (Krein-space) topology in the classification of bosonic Bogoliubov-de Gennes (BBdG) systems. In this work, we construct a BBdG realization of Hopf topology, which we dub the symplectic Hopf insulator, starting from a microscopic Bose-Hubbard generalization of the Moore-Ran-Wen model with weak on-site interactions treated within a Bogoliubov approximation. The resulting BBdG system admits a symplectic Hopf invariant, which we show to be integer-quantized for isolated bands. We establish that this topology is intrinsically delicate, requiring exactly two bosonic modes per unit cell, while remaining robust against weak interactions over a range of mass parameters. Upon terminating the three-dimensional insulator at a boundary, we find topologically protected in-gap surface states at finite excitation energy, whose protection is itself delicate. Our results establish the symplectic Hopf insulator as a robust yet delicate topological phase in weakly interacting bosonic systems lying beyond the tenfold-way classification.

cond-mat.mes-hall↗