Effect of proportion on rectification in organic co-oligomer spin rectifiers

Abstract

The rectification behaviours in organic magnetic/nonmagnetic co-oligomer spin rectifiers are investigated theoretically. It is found that both the charge current and the spin current through the device are rectified at the same time. By adjusting the proportion between the magnetic and nonmagnetic components, the threshold voltage and the rectification ratio of the rectifier are modulated. A large rectification ratio is obtained when the two components are equal in length. The intrinsic mechanism is analysed in terms of the asymmetric localization of molecular orbitals under biases. The effect of molecular length on the rectification is also discussed. These results will be helpful in the future design of organic spin diodes.

Effect of interfacial coupling on rectification in organic spin rectifiers

“…The spin rectification can be further modulated by the molecular spin states or the proportion of the co-oligomer. [18,24] Such a model design has been verified by first-principles calculations with biradical and triradical magnetic molecules. [25] It is known that the interfacial coupling in organic devices plays a crucial role for their conductivity.…”

“…Recently, we also designed a new intrinsic organic spin diode theoretically by using an asymmetric magnetic co-oligomer sandwiched between two identical electrodes, where the built-in asymmetry originates from the central molecule. [17,18] The model calculations demonstrated that the charge-current rectification and the spin-current rectification may be realized either simultaneously or respectively. The spin rectification can be further modulated by the molecular spin states or the proportion of the co-oligomer.…”

“…[11] Triggered by the great progress in molecular electronics in recent years, the design of organic spintronic devices based on organic ferromagnets has become attractive and shown promise in organic spintronic device design, such as spin valves, [12,13] spin filters, [14,15] and spin diodes. [16][17][18] Spin diodes are especially fascinating because of their important role in logical circuits. As is well known, the charge current is a scalar which is the sum of the currents with different spins.…”

Spin-excited states and rectification in an organic spin rectifier

“…[18,19] The recent progress in molecular electronics has triggered large interest in designing spintronic devices with organic ferromagnets including spin valves, [20,21] spin filters, [22,23] and spin diodes. [24][25][26] Among all the spintronic devices, spin diodes are particularly interesting due to their crucial role in logic circuits. As a new concept, molecular spin diodes have also been proposed recently.…”

“…[27,28] Recently, with the utilization of magnetic co-oligomers we theoretically designed a new intrinsic organic spin diode, where the built-in asymmetry originates from the central molecule independent of electrodes. [25,26] It has been demonstrated that both the charge-current rectification and spin-current rectification may be realized, either simultaneously or respectively, with suitable design. This theoretical model is further verified by a recent ab-intio calculation about biradical and triradical magnetic molecules.…”