SPIN-POLARISED CHARGE-CARRIER DEVICE

• US 20100123133A1
• Filed: 08/21/2009
• Published: 05/20/2010
• Est. Priority Date: 11/20/2008
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Wunderlich, Joerg, SINOVA, Jairo, IRVINE, Andrew, JUNGWIRTH, Tomas
• Granted Patent: US 9,000,433 B2
• Time in Patent Office: Days
• US Class Current: 257/48
• CPC Class Codes: G01J 4/04 Polarimeters using electric detection means G01J4/02 takes precedence
• CPC Class Codes: H01L 29/66984 Devices using spin polarized carriers

Abstract

A device comprising a channel for charge carriers comprising non-ferromagnetic semiconducting in which charge carriers exhibit spin-orbit coupling, a region of semiconducting material of opposite conductivity type to the channel and configured so as to form a junction with the channel for injecting spin-polarised charge carriers into an end of the channel and at least one lead connected to the channel for measuring a transverse voltage across the channel.

Claims

1. A device comprising:

a channel for charge carriers comprising non-ferromagnetic semiconducting material in which charge carriers exhibit spin-orbit coupling;

a region of semiconducting material of opposite conductivity type to the channel and configured so as to form a junction with the channel for injecting spin-polarised charge carriers into an end of the channel; and

at least one lead connected to the channel for measuring a transverse voltage across the channel.

2. A device according to claim 1, wherein the channel comprises a potential well confining a two-dimensional charge-carrier gas.

3. A device according to claim 2, wherein the potential well is asymmetric.

4. A device according to claim 1, wherein the semiconducting material is a crystal having no inversion symmetry.

5. A device according to claim 1, wherein the non-ferromagnetic conductive material comprises a III-V semiconducting material.

6. A device according to claim 1, wherein the conductivity type of the region is p-type and the conductivity type of the channel is n-type.

7. A device according to claim 1, further comprising:

a gate configured to apply an electric field to the channel.

8. A device according to claim 1, wherein the leads are arranged along one side or opposite sides of the channel.

9. A device according to claim 1, wherein the at least one lead comprises:

one or two leads spaced from the junction by a distance equal to about N.(x_p/2), where N is a positive integer and x_p=h/(4.m.α

), where h is Plank'"'"'s constant, m is the effective mass of the charge carrier and α

is Rashba coupling constant.

10. A device according to claim 1, wherein the at least one lead comprises:

first and second leads connected to the channel and arranged on opposite sides of the channel for measuring a voltage difference across the channel.

11. A device according to claim 10, wherein the at least one lead comprises:

third and fourth leads connected to the channel and arranged on opposite sides of the channel for measuring a voltage difference across the channel, said third and fourth leads spaced apart along the channel from the first and second leads.

12. A device according to claim 1, wherein the semiconducting material of opposite conductivity type to the channel is non-ferromagnetic.

13. A method of operating device comprising a channel for charge carriers comprising non-ferromagnetic semiconducting material in which charge carriers exhibit spin-orbit coupling, a region of semiconducting material of opposite conductivity type to the channel and configured so as to form a junction with the channel for injecting spin-polarised charge carriers into an end of the channel and at least one lead connected to the channel for measuring a transverse voltage across the channel, the method comprising:

illuminating the junction with light; and

measuring bias(es) at the lead(s).

14. A method according to claim 13, further comprising:

applying a reverse bias between the region and another end of the channel.

15. A method of fabricating a device, the method comprising:

providing a channel for charge carriers comprising non-ferromagnetic semiconducting material in which charge carriers exhibit spin-orbit coupling,

providing a region of semiconducting material of opposite conductivity type to the channel and configured so as to form a junction with the channel for injecting spin-polarised charge carriers into an end of the channel and

providing at least one lead connected to the channel for measuring a transverse voltage across the channel.

16. A method according to claim 15, the method comprising:

providing a layer structure comprising first and second overlying channels; and

etching a portion of one of the channels so as to leave the region and the channel.