Strongly localized states and giant optical absorption induced by multiple flat-bands in AA-stacked multilayer armchair graphenenanoribbons

Abstract We propose an AA-stacked multilayer graphene nanoribbon with two symmetrical armchair edges as a multiple flat-band (FB) material. Using the tight-binding Hamiltonian and Green’s function method, we find that the FBs are complete and merged into many dispersive bands. The FBs cause multiple strongly localized states (SLSs) at the sites of the odd lines in every sublayer and a giant optical absorption (GOA) at energy point 2t, where t is the electronic intralayer hopping energy between two nearest-neighbor sites. By driving an electric field perpendicular to the ribbon plane, the bandgaps of the FBs are tunable. Accordingly, the positions of the SLSs in the energy regime can be shifted. However, the position of the GOA is robust against such field, but its strength exhibits a collapse behavior with a fixed quantization step. On the contrary, by driving an electric field parallel to the ribbon plane, the completeness of FBs is destroyed. Resultantly, the SLSs and GOA are suppressed and even quenched. Therefore, such ribbons may be excellent candidates for the design of the controllable information-transmission and optical-electric nanodevices.

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Flat-band engineering in tight-binding models: Beyond the nearest-neighbor hopping

Physical Review B ◽

10.1103/physrevb.99.235118 ◽

2019 ◽

Vol 99 (23) ◽

Cited By ~ 8

Author(s):

Tomonari Mizoguchi ◽

Masafumi Udagawa

Keyword(s):

Nearest Neighbor ◽

Tight Binding ◽

Flat Band ◽

Band Engineering ◽

Binding Models

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Linear AC transport in T-stub and crossed silicene nanosystems

International Journal of Modern Physics B ◽

10.1142/s0217979218500169 ◽

2018 ◽

Vol 32 (03) ◽

pp. 1850016

Author(s):

Yun-Lei Sun ◽

En-Jia Ye

Keyword(s):

Electric Field ◽

Transport Properties ◽

External Electric Field ◽

Nearest Neighbor ◽

Transport Theory ◽

Energy Gap ◽

Local Density ◽

Tight Binding ◽

Edge State ◽

Topological Quantum

In this work, we theoretically study the linear AC transport properties in T-stub and crossed zigzag silicene nanosystems. The DC conductance and AC emittance are numerically calculated based on the tight-binding approach and AC transport theory, by considering the nearest-neighbor hopping, second-nearest-neighbor spin-orbit interaction (SOI) and external electric field. The relatively strong SOI of silicene was demonstrated to induce a topological quantum edge state in the nanosystems by the local density of states, which eliminates the AC emittance response at the Dirac point. Further investigations suggest that the SOI-induced AC transport is topologically protected from the changes of geometrical size. Moreover, the AC transport properties of these nanosystems can be tuned by the external electric field, which would open an energy gap and destroy the topological quantum state, making them trivial band insulators.

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Empirical Tight-Binding Applied to Silicon Nanoclusters

MRS Proceedings ◽

10.1557/proc-491-299 ◽

1997 ◽

Vol 491 ◽

Cited By ~ 2

Author(s):

G. Allan ◽

C. Delerue ◽

M. Lannoo

Keyword(s):

Band Structure ◽

Nearest Neighbor ◽

Good Description ◽

Tight Binding ◽

Localized States ◽

Basis Set ◽

Band Structure Calculation ◽

Minimal Basis ◽

Tight Binding Approximation ◽

Bulk Band

ABSTRACTThe calculation of the electronic structure of silicon nanostructures is used to discuss the accuracy of results obtained by the tight-binding method. We first show that the level of refinement of the tight-binding approximation must be adapted to the calculated property. For example, an accurate description of both the valence and conduction bands which can be achieved with a 3rd-nearest neighbor approximation is necessary to calculate the variation of the gap energy with the silicon crystallite size. The sp3s* model which gives a bad description of the conduction band underestimates the confinement energy but can give good results when it is used to determine the variation of the crystallite band gap with pressure. To study Si-III (BC-8) nanocrystallites, we show that a good description of the bulk band structure can be obtained with non-orthogonal tight-binding but due to the large number of nearest neighbors one must take analytical variations of the parameter with interatomic distances. The parameters involved in these expressions can be easily fitted to the bulk band structures using the k-point symmetry without requiring the use of group theory. Finally we discuss the effect of increasing the size of the minimal-basis set and we show that it would be possible to get the values of the tight-binding parameters from a first-principles localized states band structure calculation avoiding the fit to the energy dispersion curves.

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sp-band tight-binding model for the Bychkov-Rashba effect in a two-dimensional electron system including nearest-neighbor contributions from an electric field

Physical Review B ◽

10.1103/physrevb.86.085105 ◽

2012 ◽

Vol 86 (8) ◽

Cited By ~ 21

Author(s):

Christian R. Ast ◽

Isabella Gierz

Keyword(s):

Electric Field ◽

Nearest Neighbor ◽

Tight Binding ◽

Electron System ◽

Two Dimensional ◽

Tight Binding Model ◽

Rashba Effect ◽

Dimensional Electron ◽

Binding Model ◽

Dimensional Electron System

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BLOCH DYNAMICS IN SPATIALLY LOCAL INHOMOGENEOUS ELECTRIC FIELDS

International Journal of High Speed Electronics and Systems ◽

10.1142/s0129156401000903 ◽

2001 ◽

Vol 11 (02) ◽

pp. 425-453

Author(s):

JOSEPH P. REYNOLDS ◽

GERALD J. IAFRATE ◽

JUN HE

Keyword(s):

Electric Field ◽

Electric Fields ◽

Nearest Neighbor ◽

Constant Electric Field ◽

Tight Binding ◽

Homogeneous Field ◽

Wannier Functions ◽

Field Dependent ◽

Bloch Electrons ◽

Special Case

The influence of local inhomogeneities on the electric field dependent properties of Bloch electrons is studied. The homogeneous electric field is described through the use of the vector potential, and the instantaneous Wannier functions of the homogeneous field dependent Hamiltonian are used as bases states to depict Bloch dynamics and properties. Model examples are treated using Slater-Koster inhomogeneities and nearest-neighbor tight-binding band structure in a one dimensional, single-band analysis. Detailed analysis is presented for the special case of a constant electric field; here the influence of localization due to the presence of the electric field is shown to clearly affect the energy spectrum of the Bloch electron for a single and double impurity configuration.

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ELECTRONIC STATES AND LOCAL DENSITY OF STATES NEAR GRAPHENE CORNER EDGE

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194512006058 ◽

2012 ◽

Vol 11 ◽

pp. 151-156 ◽

Cited By ~ 1

Author(s):

YUJI SHIMOMURA ◽

YOSITAKE TAKANE ◽

KATSUNORI WAKABAYASHI

Keyword(s):

Density Of States ◽

Nearest Neighbor ◽

Local Density ◽

Tight Binding ◽

Localized States ◽

Destructive Interference ◽

Edge States ◽

Local Density Of States ◽

Binding Model ◽

Recursion Method

We study that stability of edge localized states in semi-infinite graphene with a corner edge of the angles 60°, 90°, 120° and 150°. We adopt a nearest-neighbor tight-binding model to calculate the local density of states (LDOS) near each corner edge using Haydock's recursion method. The results of the LDOS indicate that the edge localized states stably exist near the 60°, 90°, and 150° corner, but locally disappear near the 120° corner. By constructing wave functions for a graphene ribbon with three 120° corners, we show that the local disappearance of the LDOS is caused by destructive interference of edge states and evanescent waves.

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