scholarly journals Phase Transition in a One-dimensional Extended Peierls–Hubbard Model with a Pulse of Oscillating Electric Field: II. Linear Behavior in Neutral-to-Ionic Transition

2004 ◽  
Vol 73 (10) ◽  
pp. 2879-2886 ◽  
Author(s):  
Kenji Yonemitsu
Keyword(s):  
Phase Transition ◽  
Electric Field ◽  
Hubbard Model ◽  
One Dimensional ◽  
Linear Behavior ◽  
Ionic Transition ◽  
Oscillating Electric Field

One-dimensionality and neutral-to-ionic transition of some mixed-stack charge-transfer complexes

2002 ◽  
Vol 12 (9) ◽  
pp. 357-360
Author(s):  
M. Buron ◽  
E. Collet ◽  
M. H. Lemée-Cailleau ◽  
H. Cailleau ◽  
T. Luty ◽  
...  
Keyword(s):  
Phase Transition ◽  
Charge Transfer ◽  
Charge Transfer Complexes ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
Giant Dielectric ◽  
Ionic Transition ◽  
The One ◽  
Ct Complexes ◽  
Dimerization Process

Mixed-stack charge-transfer (CT) complexes undergoing the neutral-ionic (N-I) phase transition are molecular materials formed of stacks where electron donor (D) and acceptor (A) molecules regularly alternate. In the N phase, the CT is low and molecules are situated on inversion centers, while in the I phase, the increase of CT is accompanied by a lattice distortion (dimerization process and symmetry breaking). The one-dimensional (1D) architecture triggers the chain multistability by stabilizing lattice-relaxed (LR)-CT excitations ...D° A° D° A° $(D^+A^-)(D^+A^-)(D^+A^-)$ Do A" D° A° D°... These 1D nano-scale objects are at the heart of the equilibrium N-I phase transition and govern the fascinating physical properties such as giant dielectric response or photo-induced phase transformations. In this contribution, the 1D character of these critical excitations will be demonstrated by direct observation using high resolution X-Ray diffraction.

scholarly journals Hubbard model analysis of the double photoionization of aromatic hydrocarbons

2018 ◽  
Vol 32 (06) ◽  
pp. 1850083
Author(s):  
D. L. Huber
Keyword(s):  
Hubbard Model ◽  
Aromatic Hydrocarbons ◽  
Organic Molecules ◽  
Low Energy ◽  
Ion Concentration ◽  
One Dimensional ◽  
Double Photoionization ◽  
Simultaneous Emission ◽  
Linear Behavior ◽  
The One

Using the one-dimensional Hubbard model as a guide, the peaks in the double photoionization in a variety of aromatic hydrocarbons and related molecules are analyzed. In all the aromatic hydrocarbons that have been studied, there are peaks in the 2[Formula: see text] ion concentration that are 40 eV above threshold. These peaks arise from the emission of electrons from a Hubbard state associated with carbon atoms on the perimeter of the molecule. Pyrene and coronene also have low energy peaks 10 eV above threshold that are associated with the carbon atoms inside the perimeter. The linear behavior of the 2[Formula: see text] ion concentration above the two-electron ionization energy that is found in organic molecules lacking periodic symmetry in their perimeter atoms is associated with the simultaneous emission of two photoelectrons with approximately equal kinetic energies moving in opposite directions.

Photon-assisted transport through a 1D-dot-graphene similar to STM model device

2017 ◽  
Vol 31 (21) ◽  
pp. 1750142
Author(s):  
Zhiyun Zhao ◽  
Yi Min ◽  
Pengxia Zhou ◽  
Yanyan Huang ◽  
Chonggui Zhong
Keyword(s):  
Electric Field ◽  
Optoelectronic Devices ◽  
Transmission Probability ◽  
Green Function Method ◽  
One Dimensional ◽  
Current Voltage ◽  
Oscillating Electric Field ◽  
Step Growth ◽  
Nonequilibrium Green Function ◽  
Model Device

By using the nonequilibrium Green function method, the photon-assisted electron transport through a graphene-based device similar to STM model is studied theoretically and numerically. The device is composed of a single central site (quantum dot) modulated by an oscillating electric field, a one-dimensional quantum wire and a two-dimensional graphene sheet. Some interesting results on transmission probability and current–voltage ([Formula: see text]–[Formula: see text]) characteristics of the device are given in this paper. In the presence of an oscillating electric field, we find that besides the central two transmission peaks caused by graphene part, there appear photon-assisted peaks which are distributed on both sides of the Fermi level. The positions of the photon-assisted peaks are linear to the frequency of the oscillating electric field, and the widths of the photon-assisted peaks are relevant to the amplitude of the oscillating electric field. It is found that the current–voltage graphs exhibit step growth due to the existence of photon-assisted tunneling. We hope these results may have guidance meaning for the fabrication of optoelectronic devices.

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