Modulation of circular current and associated magnetic field in a molecular junction: A new approach

Abstract

A new proposal is given to control local magnetic field in a molecular junction. In presence of finite bias a net circular current is established in the molecular ring which induces a magnetic field at its centre. Allowing a direct coupling between two electrodes, due to their close proximity, and changing its strength we can regulate circular current as well as magnetic field for a wide range, without disturbing any other physical parameters. We strongly believe that our proposal is quite robust compared to existing approaches of controlling local magnetic field and can be verified experimentally.

Possible Routes for Efficient Thermo‐Electric Energy Conversion in a Molecular Junction

“…where different sub‐Hamiltonians are associated with different parts of the molecular junction, and, we describe all these Hamiltonians within a tight‐binding (TB) framework which is extremely suitable in studying transport in molecular systems, especially in absence of any kind of electron‐electron (e‐e) correlation ,. The explicit forms of these sub‐Hamiltonians are given as follows.…”

Charge-based re-programmable logic device with built-in memory: New era in molecular electronics

“…where H M represents the molecular Hamiltonian, H S and H D are the Hamiltonians for the S and D electrodes, and the Hamiltonian H tun is associated with the coupling of the molecule with side-attached electrodes. All these Hamiltonians are described by a similar kind of TB form and within non-interacting picture the general form of Hamiltonian reads as 14,16…”

“…For the drain electrode the wave amplitude at any particular site l (say) becomes quite simpler as there is no reflection from the drain end and gets the form te ikla , where t is the transmission coefficient, and, its absolute square gives the transmission probability. Using the above wave forms of incident and transmitted waves, we solve the coupled linear equations involving wave amplitudes at different lattice sites for different injecting electron energies, and then we calculate bond current density between any two neighboring sites (say, m and m + 1) of the molecule following the expression 14,16,24…”

“…Integrating this current density we compute bond current for a particular bias voltage V and it becomes 14,16,27…”

High degree of current rectification at nanoscale level

“…To evaluate transmission probability across the conducting junction we solve a set of coupled linear equations containing wave amplitudes of distinct lattice sites of the chain 21,22 . Assuming a plane wave incidence, we can write the wave amplitude at any site n of the source as A n = e ikn + re −ikn , where k is the wave-vector and r being the reflection coefficient.…”