Progress to Opto-Spintronics

Researchers from Sweden, Finland and Japan have now constructed a semiconductor component in which information can be efficiently exchanged between electron spin and light – at room temperature and above.

Semiconductor spintronics have potential for opto-spintronics, which will allow integration of spin-based information processing/storage with photon-based information transfer/communications. Unfortunately, progress has so far been severely hampered by the failure to generate nearly fully spin-polarized charge carriers in semiconductors at room temperature.

Researchers have demonstrated successful generation of conduction electron spin polarization exceeding 90% at room temperature without a magnetic field in a non-magnetic all-semiconductor nanostructure, which remains high even up to 110 °C. Previous research had achieved a highest electron spin polarization of around 60% at room temperature, untenable for large-scale practical applications.

This is accomplished by remote spin filtering of InAs quantum-dot electrons via an adjacent tunnelling-coupled GaNAs spin filter. They further show that the quantum-dot electron spin can be remotely manipulated by spin control in the adjacent spin filter, paving the way for remote spin encoding and writing of quantum memory as well as for remote spin control of spin–photon interfaces. This work demonstrates the feasibility to implement opto-spintronic functionality in common semiconductor nanostructures.

Nature Photonics – Room-temperature electron spin polarization exceeding 90% in an opto-spintronic semiconductor nanostructure via remote spin filtering

What is spintronics?
Spintronics is a technology that uses both the charge and the spin of electrons to process and carry information.
The spin of an electron can be envisioned as arising when the electron rotates clockwise or anticlockwise around its axis, in the same way that the Earth rotates around its axis. The two directions of rotation are called “up” and “down”. In the electronic technology used today, the electron charge is used to represent 0 and 1, and in this way carry information. In a corresponding way, the information can be represented in spintronics using the spin state of the electrons.

SOURCES – Nature Photonics, Linköping University
Written by Brian Wang,