Impact of magnetic fields on polaron dynamics in low-dimensional systems

Abstract

We study the impact of an external magnetic field on the long-range electron transport in quasi-one-dimensional materials, such as polypeptides, (semi-) conducting polymers and macromolecules, taking into account the electron-lattice interaction. At relatively strong electron-lattice interaction extra electrons get self-trapped in the deformation potential well and form stable bound states, called large polarons which in the continuum approximation are known as solitons. Here we do not use the continuum approximation but solve the system of discrete nonlinear equations numerically. We show that the impact of a magnetic field on polaron dynamics depends not only on the field strength, but also on the parameter values of the system which define the properties of solitons such as their energy, amplitude and width of localisation. We also study the impact of a magnetic field on a polaron created by a donor complex on a chain.

Figures (14)

• Figure 1: Time evolution of an Amide-I polaron profile on a Donor-Polypeptide system. ($\chi = 174.1$, $W=37$, $\sigma = 0.0857$, $D_d=0.6$, $J_d=0.6$, $x_d=0.2$, $v_d=0.6$, $m_d=5$). A small polaron overtakes a larger one.
• Figure 2: Amide-I type polaron ($\chi = 174.19$, $W=37$, $\sigma = 0.0857$) as a function of $n$ : a) profile $|\Psi|^2$; b) site displacement $u$.
• Figure 3: Amide-I type polaron: acceleration as a function of $B$ for different boosting velocities.
• Figure 4: Amide-I polaron ( $\chi = 174.19$, $W=37$, $\sigma = 0.0857$) a) : critical $B$ as a function of $L_y$; b) acceleration as a function of $B$ for different $L_y$.
• Figure 5: Extra electron in a polypeptide $(\chi = 54$, $W=0.62$, $\sigma = 0.0041$): acceleration as a function of $B$ for different boosts