University of California

Jing Shi

Junxue Li

Pierre M Petroff

Roger Lake

David D Awschalom

Mohammed Aldosary

Chi Tang

Yadong Xu

James M Kikkawa

Systems and methods for spin-based detection of electromagnetic radiation at terahertz and sub-terahertz frequencies is provided. The detector can include a heterostructure and an electrical circuit. The heterostructure can include a first layer formed of an antiferromagnetic material (AFM) in contact with a second layer of a heavy metal (HM) and a third layer. The third layer can generate an effective field oriented approximately parallel to an easy axis of the first layer and approximately parallel to a propagation direction of electromagnetic radiation. The circuit can be in electrical communication with the second layer. The first layer can inject a spin current into the second layer in response to receipt of electromagnetic radiation having a sub-terahertz or terahertz frequency. The second layer can convert the injected spin current into a potential difference. The circuit can be configured to output a signal corresponding to the potential difference.

Spin-based detection of terahertz and sub-terahertz electromagnetic radiation

Systems and methods for spin-based detection of electromagnetic radiation at terahertz and sub-terahertz frequencies is provided. The detector can include a heterostructure, a magnetic field generator, and an electrical circuit. The heterostructure can include a first layer formed of an antiferromagnetic material (AFM) in contact with a second layer of a heavy metal (HM) or a topological insulator. The magnetic field generator can generate a magnetic field oriented approximately parallel to an easy axis of the first layer and approximately parallel to a propagation direction of electromagnetic radiation. The circuit can be in electrical communication with the second layer. The first layer can inject a spin current into the second layer in response to receipt of electromagnetic radiation having a sub-terahertz or terahertz frequency. The second layer can convert the injected spin current into a potential difference. The circuit can be configured to output a signal corresponding to the potential difference.

Pure spin current devices are provided. The devices include sandwich structures of metal/magnetic insulator/metal. A first current injected in a first metal layer generates a pure spin current. The spin current can be switched between 'on' and 'off' states by controlling an in-plane magnetization orientation of the magnetic insulator. In the &#x201c;on&#x201d; state, the pure spin current is transmitted from the first metal layer to the second metal layer, through the magnetic insulator layer. The pure spin current in the second metal layer induces generation of a second charge current. In the &#x201c;off&#x201d; state, the pure spin current is absorbed at the interface between the first metal layer and the metal insulator. Such structures can serve as pure spin current valve devices or provide analog functionality, as rotating the in-plane magnetization provides analog sinusoidal modulation of the spin current.

Spin current devices and methods of fabrication thereof

Submicron ferromagnets, of selected size and spacing, are introduced into semiconductor by means of ion implantation and subsequent heat treatments. The resulting semiconductor contains ferromagnets at high density and which exhibit Curie temperatures exceeding room temperature. The semiconductor retains its intrinsic physical properties, such as optical and transport properties, after incorporation of the ferromagnetic nanostructures.

Growing community of inventors

Riverside, CA, United States of America

Jing Shi