scholarly journals Bloch oscillations of the Holstein polaron in the process of its uniform motion along a chain in a constant electric field

2019 ◽  
pp. 1-30
Author(s):  
Alevtina Nikolaevna Korshunova ◽  
Victor Dmitrievich Lakhno
Author(s):  
A.N. Korshunova ◽  
V.D. Lakhno

Various regimes of a charge motion along a chain in a constant electric field are investigated. This motion is simulated on the basis of the Holstein model. Earlier studies demonstrate a possibility of a uniform motion of a charge in a constant electric field over very long distances. For small values of the electric field intensity a Holstein polaron can move at a constant velocity. As the electric field intensity increases, a charge motion acquires oscillatorily character, performing Bloch oscillations. Since the charge motion depends on the whole set of the system parameters the character of the motion depends not only on the value of the electric field intensity. Therefore, the electric field intensity for which the uniform motion takes place differs for chains with different parameters. The character of the charge motion and distribution is considered in chains with different values of the constant of coupling between the charge and the displacements of the chain. We showed that the values of the electric field intensity for which the regime of a charge motion changes are different in chains with different values of the coupling constant. We also demonstrated that for one and the same value of the electric field intensity, in chains with different values of the coupling constant either a uniform motion or an oscillatory motion, or a stationary polaron can be observed.


Author(s):  
A.N. Korshunova ◽  
V.D. Lakhno

In connection with the development of molecular nanobioelectronics, the main task of which is the construction of electronic devices based on biological molecules, the problems of charge transfer in such extended molecules as DNA are of increasing interest. The relevance of studying the charges motion in one-dimensional molecular chains is primarily associated with the possibility of using these chains as wires in nanoelectronic devices. Current carriers in one-dimensional chains are self-trapped electronic states, which have the form of polaron formations. In this paper we investigate the motion of the Holstein polaron in the process of its uniform motion along the chain in a constant electric field. It is known that during uniform motion along the chain in a weak electric field, the polaron experiences small oscillations of its shape. These oscillations are associated with the discreteness of the chain and are due to the presence of the Peierls-Nabarro potential in the discrete chain. Previous investigations have shown that for certain parameters of the chain, there is the possibility of uniform charge motion in a constant electric field over very large distances. The charge motion with a constant velocity is possible for small values of the electric field intensity. With an increase in the electric field intensity, the charge goes into an oscillatory regime of motion with Bloch oscillations. The calculations performed in this work showed that the elements of Bloch oscillations also appear during stationary motion of the polaron along the chain. Thus, it is shown that the Holstein polaron, uniformly moving along the chain in a constant electric field, experiences not only Peierls-Nabarro oscillations, but also low-amplitude oscillations with a Bloch period.


2020 ◽  
Vol 90 (9) ◽  
pp. 1528
Author(s):  
А.Н. Коршунова ◽  
В.Д. Лахно

The numerical experiments which demonstrate the possibility of charge transfer in a homogeneous Poly G / Poly C DNA chain in the constant electric field have been carried out. As a model, which describes the dynamics of a DNA molecule, was considered the nonlinear Peyrard–Bishop–Holstein model. It is shown that the polaron can move along the chain at a constant velocity over long distances for small values of electric field intensity. With an increase in the value of the electric field intensity the uniform motion of the charge is not observed, the charge goes into an oscillatory mode of motion with Bloch oscillations.


Author(s):  
А.Н. Коршунова ◽  
A.N. Korshunova

In connection with the development of molecular nanobioelectronics, the main task of which is the construction of electronic devices based on biological molecules, the problems of charge transfer in such extended molecules as DNA are of increasing interest. The relevance of studying the charges motion in one-dimensional molecular chains is primarily associated with the possibility of using these chains as wires in nanoelectronic devices. Current carriers in one-dimensional chains are self-trapped electronic states, which have the form of polaron formations. In this paper we investigate the motion of the Holstein polaron in the process of its uniform motion along the chain in a constant electric field. It is known that during uniform motion along the chain in a weak electric field, the polaron experiences small oscillations of its shape. These oscillations are associated with the discreteness of the chain and are due to the presence of the Peierls-Nabarro potential in the discrete chain. Previous investigations have shown that for certain parameters of the chain, there is the possibility of uniform charge motion in a constant electric field over very large distances. The charge motion with a constant velocity is possible for small values of the electric field intensity. With an increase in the electric field intensity, the charge goes into an oscillatory regime of motion with Bloch oscillations. The calculations performed in this work showed that the elements of Bloch oscillations also appear during stationary motion of the polaron along the chain. Thus, it is shown that the Holstein polaron, uniformly moving along the chain in a constant electric field, experiences not only Peierls-Nabarro oscillations, but also low-amplitude oscillations with a Bloch period.


Author(s):  
N.S. Fialko ◽  
V.D. Lakhno

In a number of publications about biophysical experiments on the transfer of a charge to DNA, it is assumed that charge is transferred via a super-exchange mechanism at short distances of 2–3 nucleotide pairs, and in long fragments the charge forms a polaron that moves along the chain under the influence of temperature fluctuations. Using numerical simutation, we investigate the dynamics of a polaron of small radius in a homogeneous chain plaiced in constant electric field at a finite temperature. It is shown that there is no charge transfer by the polaron mechanism, i.e. there is no sequential movement of the polaron from site to site, in chains with parameter valuess corresponding to homogeneous adenine DNA fragments. The “polaron or delocalized state” check is based on the control of the average characteristics: the delocalization parameter, the position of the maximum probability, and the maximum modulus displacement. The dynamics of individual trajectories is also considered. Without electric field, there is a mode of switching between the states "stationary polaron – delocalized state", and a new polaron arises at a random site of the chain. In the chain placed in field with constant intensity, the averaged charge moves in the direction of the field, but the transfer occurs in a delocalized state.


2002 ◽  
Vol 12 (02) ◽  
pp. 583-592 ◽  
Author(s):  
ROBERT A. SURIS ◽  
IVAN A. DMITRIEV

An analysis has been presented of electron localization in ideal 2D and 3D quantum dot superlattices (QDSL) in a homogeneous dc electric field and of Bloch oscillations in such structures. A very strong dependence of the ideal QDSL spectrum and wave functions on the field orientation is demonstrated. Bloch oscillations (BO) in QDSL are performed at two (or three for 3D QDSL) main Stark frequencies, which can be independently tuned by variation of field value and orientation. Due to the strong dependence of spectrum on field orientation, in QDSL intraminiband scattering processes can be almost totally suppressed. That allows to enlarge the BO lifetime by two orders of magnitude as compared with conventional quantum well superlattices.


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