scholarly journals Time Evolution of Floquet States in Graphene

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
F. Manghi ◽  
M. Puviani ◽  
F. Lenzini
Keyword(s):  
Band Structure ◽  
Time Evolution ◽  
Electromagnetic Fields ◽  
Graphene Nanoribbons ◽  
Electronic States ◽  
The State ◽  
Time Dependent ◽  
Edge States ◽  
State Population ◽  
Floquet States

Based on a solution of the Floquet Hamiltonian we have studied the time evolution of electronic states in graphene nanoribbons driven out of equilibrium by time-dependent electromagnetic fields in different regimes of intensity, polarization, and frequency. We show that the time-dependent band structure contains many unconventional features that are not captured by considering the Floquet eigenvalues alone. By analyzing the evolution in time of the state population we have identified regimes for the emergence of time-dependent edge states responsible for charge oscillations across the ribbon.

scholarly journals Band Structure and Energy Level Alignment of Chiral Graphene Nanoribbons on Silver Surfaces

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3303
Author(s):  
Martina Corso ◽  
Rodrigo E. Menchón ◽  
Ignacio Piquero-Zulaica ◽  
Manuel Vilas-Varela ◽  
J. Enrique Ortega ◽  
...  
Keyword(s):  
Energy Level ◽  
Band Structure ◽  
Work Function ◽  
Graphene Nanoribbons ◽  
Interface Energy ◽  
Edge State ◽  
Edge States ◽  
Energy Level Alignment ◽  
Step Density ◽  
Silver Surfaces

Chiral graphene nanoribbons are extremely interesting structures due to their narrow band gaps and potential development of spin-polarized edge states. Here, we study their band structure on low work function silver surfaces. The use of a curved Ag single crystal provides, within the same sample, regions of disparate step structure and step density. Whereas the former leads to distinct azimuthal growth orientations of the graphene nanoribbons atop, the latter modulates the substrate’s work function and thereby the interface energy level alignment. In turn, we disclose the associated charge transfer from the substrate to the ribbon and assess its effect on the nanoribbon’s properties and the edge state magnetization.

scholarly journals The time-dependent angular analysis of Bd → KSℓℓ, a new benchmark for new physics

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Sébastien Descotes-Genon ◽  
Martín Novoa-Brunet ◽  
K. Keri Vos
Keyword(s):  
Time Evolution ◽  
Form Factors ◽  
New Physics ◽  
Time Dependent ◽  
Angular Analysis ◽  
Time Dependent Analysis ◽  
Tensor Operators

Abstract We consider the time-dependent analysis of Bd→ KSℓℓ taking into account the time-evolution of the Bd meson and its mixing into $$ {\overline{B}}_d $$ B ¯ d . We discuss the angular conventions required to define the angular observables in a transparent way with respect to CP conjugation. The inclusion of time evolution allows us to identify six new observables, out of which three could be accessed from a time-dependent tagged analysis. We also show that these observables could be obtained by time-integrated measurements in a hadronic environment if flavour tagging is available. We provide simple and precise predictions for these observables in the SM and in NP models with real contributions to SM and chirally flipped operators, which are independent of form factors and charm-loop contributions. As such, these observables provide robust and powerful cross-checks of the New Physics scenarios currently favoured by global fits to b → sℓℓ data. In addition, we discuss the sensitivity of these observables with respect to NP scenarios involving scalar and tensor operators, or CP-violating phases. We illustrate how these new observables can provide a benchmark to discriminate among the various NP scenarios in b → sμμ. We discuss the extension of these results for Bs decays into f0, η or η′.

scholarly journals Coagulation Processes with Gibbsian Time Evolution

2012 ◽  
Vol 49 (03) ◽  
pp. 612-626
Author(s):  
Boris L. Granovsky ◽  
Alexander V. Kryvoshaev
Keyword(s):  
Stochastic Process ◽  
Recurrence Relation ◽  
Time Evolution ◽  
Nonnegative Function ◽  
Gibbs Distribution ◽  
Time Dependent ◽  
Explicit Solutions ◽  
Gibbs Distributions ◽  
Giant Cluster ◽  
Positive Integers

We prove that a stochastic process of pure coagulation has at any timet≥ 0 a time-dependent Gibbs distribution if and only if the rates ψ(i,j) of single coagulations are of the form ψ(i;j) =if(j) +jf(i), wherefis an arbitrary nonnegative function on the set of positive integers. We also obtain a recurrence relation for weights of these Gibbs distributions that allow us to derive the general form of the solution and the explicit solutions in three particular cases of the functionf. For the three corresponding models, we study the probability of coagulation into one giant cluster by timet> 0.

The Energy Band Structure of Polyacene with Soliton Excitation

1997 ◽  
Vol 11 (11) ◽  
pp. 477-483 ◽  
Author(s):  
Z. J. Li ◽  
H. B. Xu ◽  
K. L. Yao
Keyword(s):  
Band Structure ◽  
Charge Density ◽  
Energy Band ◽  
Energy Gap ◽  
Electronic States ◽  
Energy Band Structure ◽  
Energy Spectra ◽  
Energy Band Gap ◽  
The One ◽  
Soliton Excitation

Starting from the extensional Su–Schrieffer–Heeger model taking into account the effects of interchain coupling, we have studied the energy spectra and electronic states of soliton excitation in polyacene. The dimerized displacement u0 is found to be similar to the case of trans-polyacetylene, and equals to 0.04 Å. The energy-band gap is 0.38 eV, in agreement with the results derived by other authors. Two new bound electronic states have been found in the conduction band and in the valence band, which is different from the one of trans-polyacetylene. There exists two degenerate soliton states in the center of energy gap. Furthermore, the distribution of charge density and spin density have been discussed in detail.

Relating Localized Electronic States to Host Band Structure In Rare-Earth-Activated Optical Materials

2001 ◽  
Vol 12 (12) ◽  
pp. 64 ◽  
Author(s):  
Charles W. Thiel ◽  
Herve Cruguel ◽  
Huasheng Wu ◽  
Yongchen Sun ◽  
Gerald J. Lapeyre ◽  
...  
Keyword(s):  
Rare Earth ◽  
Band Structure ◽  
Optical Materials ◽  
Electronic States

Tailoring plasmon excitations in α − T3 armchair nanoribbons

2021 ◽  
Author(s):  
Andrii Iurov ◽  
Liubov Zhemchuzhna ◽  
Godfrey Gumbs ◽  
Danhong Huang ◽  
Paula Fekete ◽  
...  
Keyword(s):  
Energy Gap ◽  
Graphene Nanoribbons ◽  
Electronic States ◽  
Landau Damping ◽  
Next Generation ◽  
Polarization Function ◽  
Edge Termination

Abstract We have calculated and investigated the electronic states, dynamical polarization function and the plasmon excitations for α − T3 nanoribbons with armchair-edge termination. The obtained plasmon dispersions are found to depend significantly on the number of atomic rows across the ribbon and the energy gap which is also determined by the nanoribbon geometry. The bandgap appears to have the strongest effect on both the plasmon dispersions and their Landau damping. We have determined the conditions when relative hopping parameter α of an α − T3 lattice has a strong effect on the plasmons which makes our material distinguished from graphene nanoribbons. Our results for the electronic and collective properties of α − T3 nanoribbons are expected to find numerous applications in the development of the next-generation electronic, nano-optical and plasmonic devices.

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