scholarly journals Simplified model for the energy levels of quantum rings in single layer and bilayer graphene

2010 ◽  
Vol 81 (4) ◽  
Author(s):  
M. Zarenia ◽  
J. Milton Pereira ◽  
A. Chaves ◽  
F. M. Peeters ◽  
G. A. Farias
Keyword(s):  
Energy Levels ◽  
Single Layer ◽  
Bilayer Graphene ◽  
Simplified Model ◽  
Quantum Rings

The Hartman effect in graphene systems

2017 ◽  
Vol 31 (01) ◽  
pp. 1650250 ◽  
Author(s):  
Mohammad Esmailpour ◽  
Hakimeh Mohammadpour ◽  
Hamideh Hadavifar
Keyword(s):  
Incident Energy ◽  
Energy Levels ◽  
Single Layer ◽  
Normal Incidence ◽  
Bilayer Graphene ◽  
Single Layer Graphene ◽  
Monolayer Graphene ◽  
Tunneling Time ◽  
Layer Graphene ◽  
Hartman Effect

The present paper investigates that the tunneling time for bilayer graphene potential barrier with monolayer graphene leads to all range of energy. Numerical results reveal that parameters such as the incident energy and angle plays a significant role in inducing of the Hartman effect. In contrast to single-layer graphene, in the bilayer graphene, due to the chirality of quasi-particles induction of Klein and Hartman effects occur in the normal incidence case. Moreover, it is demonstrated that even for energy levels above barrier, the Hartman effect is present.

Single Layer vs Bilayer Graphene: A Comparative Study of the Effects of Oxygen Plasma Treatment on Their Electronic and Optical Properties

2011 ◽  
Vol 115 (33) ◽  
pp. 16619-16624 ◽  
Author(s):  
Amirhasan Nourbakhsh ◽  
Mirco Cantoro ◽  
Alexander V. Klekachev ◽  
Geoffrey Pourtois ◽  
Tom Vosch ◽  
...  
Keyword(s):  
Optical Properties ◽  
Comparative Study ◽  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Single Layer ◽  
Bilayer Graphene ◽  
Oxygen Plasma Treatment ◽  
Electronic And Optical Properties

scholarly journals Lamb shift of energy levels in quantum rings

2014 ◽  
Vol 48 (2) ◽  
pp. 025401 ◽  
Author(s):  
G Yu Kryuchkyan ◽  
O Kyriienko ◽  
I A Shelykh
Keyword(s):  
Lamb Shift ◽  
Energy Levels ◽  
Quantum Rings

scholarly journals Energy levels of hybrid monolayer-bilayer graphene quantum dots

2016 ◽  
Vol 93 (16) ◽  
Author(s):  
M. Mirzakhani ◽  
M. Zarenia ◽  
S. A. Ketabi ◽  
D. R. da Costa ◽  
F. M. Peeters
Keyword(s):  
Quantum Dots ◽  
Energy Levels ◽  
Graphene Quantum Dots ◽  
Bilayer Graphene

scholarly journals Electronic and magnetic properties of two dimensional crystals

2021 ◽  
Author(s):  
◽  
Hani Hatami
Keyword(s):  
Magnetic Properties ◽  
Transport Properties ◽  
Energy Levels ◽  
Bilayer Graphene ◽  
Orbit Coupling ◽  
Monolayer Graphene ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Electronic And Magnetic Properties

<p>In the last few years, two dimensional crystals have become available for experimental studies. Good examples of such systems are monolayers and bilayers of graphene and monolayers of transition metal dichalcogenides such as MoS₂ and WSe₂. The availability of two dimensional crystals has encouraged physicists to study the electronic and magnetic properties of such systems. This thesis adds to the theoretical knowledge about electronic and magnetic properties of two dimensional crystals with the focus on graphene and MoS₂.  As a general theme in this thesis, we calculate how in general these systems interact with electric and magnetic fields and what their response is to such stimuli. In particular, we have studied the response of monolayer graphene to an in-plane electric field. We have also looked at spin-orbit coupling effects that arise from applying perpendicular or in-plane external electric fields, especially their consequences for transport properties of bilayer graphene. We investigated the electronic properties of charge carriers confined in a mesoscopic ring structure using a gate voltage in bilayer graphene. We also showed how spin-orbit coupling can affect the electrical properties of such rings. We found how spin-orbit coupling can affect the transport properties in bilayer graphene. We also investigated the RKKY or indirect exchange coupling between magnetic moments in monolayer MoS₂ through calculating wave vector dependent spin susceptibility.  We examined the electronic properties of electrons and holes confined electrostatically into a bilayer graphene ring. We presented an analytical solution for finding energy levels in the ring. We showed that the magnetic field dependence of the lowest energy level with fixed angular momentum in bilayer graphene rings, in contrast to usual semiconductor quantum rings, is not parabolic but displays an asymmetric “Mexican hat“. We found that introducing spin-orbit coupling in the ring can flatten this Mexican hat.  We studied the effect of an orbital Rashba type effect, induced by an in-plane electric field in monolayer graphene. Using perturbation theory, we showed that this term can affect the energy levels in a crossed electric and magnetic field such that the electron and hole levels repel each other. We calculated the AC transport of monolayer graphene in the linear-response regime and showed that taking the orbital Rashba term into account casts doubt on the universality of the minimum conductivity of monolayer graphene.  We studied the effect of spin-orbit coupling in transport properties of bilayer graphene systems by calculating tunnelling through npn and np junctions. We showed that at sufficiently large spin-orbit strength, normal transmission through a barrier which is forbidden in bilayer graphene becomes finite. We predict that in a weak Rashba spin-orbit regime, outgoing electrons show signals which are spin polarized. We also showed that considering spin-orbit coupling only in the barrier of an npn junction can invert the spin of the incoming electrons.  Finally, we obtained analytical expressions for the wave vector-dependent static spin susceptibility of monolayer transition metal dichalcogenides, considering both the electron-doped and hole-doped cases. These results are then applied to the calculations of physical observables of monolayer MoS₂. We claculated that the hole-mediated RKKY exchange interaction for in-plane impurity-spin components decays with a different power law from what is expected for a two-dimensional Fermi liquid. In contrast, we calculated that the out-of-plane spin response shows the conventional long-range behaviour.</p>

Frictional Drag Effect between Massless and Massive Fermions in Single-Layer/Bilayer Graphene Heterostructures

Nano Letters ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 1396-1402
Author(s):  
Lijun Zhu ◽  
Lin Li ◽  
Ran Tao ◽  
Xiaodong Fan ◽  
Xinyi Wan ◽  
...  
Keyword(s):  
Single Layer ◽  
Bilayer Graphene ◽  
Drag Effect ◽  
Frictional Drag

scholarly journals Evolution of quasi-bound states in the circular n–p junction of bilayer graphene under magnetic field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Haijiao Ji ◽  
Yueting Pan ◽  
Haiwen Liu
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Bound States ◽  
Local Density ◽  
Energy Levels ◽  
Bilayer Graphene ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Weak Magnetic Fields ◽  
The Magnetic Field

Abstract Electron in gapless bilayer graphene can form quasi-bound states when a circular symmetric potential is created in bilayer graphene. These quasi-bound states can be adjusted by tuning the radius and strength of the potential barrier. We investigate the evolution of quasi-bound states spectra in the circular n–p junction of bilayer graphene under the magnetic field numerically. The energy levels of opposite angular momentum split and the splitting increases with the magnetic field. Moreover, weak magnetic fields can slightly shift the energy levels of quasi-bound states. While strong magnetic fields induce additional resonances in the local density states, which originates from Landau levels. We demonstrate that these numerical results are consistent with the semiclassical analysis based on Wentzel–Kramers–Brillouin approximation. Our results can be verified experimentally via scanning tunneling microscopy measurements.

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