Direct electrical detection of current-induced spin polarization due to spin-momentum locking in topological insulators

A device for directly electrically detecting current-generated spin polarization in topological insulators, comprising:

• a first contact and fourth contact on a layer of Bi2Se3 to produce a spin;
• a second magnetic contact comprising a ferromagnet/oxide tunnel barrier contact as a detector;
• wherein the ferromagnet/oxide tunnel barrier comprises a layer of Co and a layer of MgO on top of a layer of graphene;
• a third reference contact comprising nonmagnetic metal as the reference contact;
• a current to the first contact and fourth contact to produce a net spin polarization;
• and
• the spin polarization manifesting as a voltage between the second magnetic contact and third reference contact.

A method for direct electrical access to current-induced spin polarization due to spin-momentum locking of the topologically protected surface states in topological insulators comprising:

• depositing a first contact, second contact, and third contact wherein the second contact comprises a ferromagnet/oxide tunnel barrier contact and wherein the third contact comprises a nonmagnetic metal contact;
• wherein the ferromagnet/oxide tunnel barrier comprises a layer of Co and a layer of MgO on top of a layer of graphene;
• applying an unpolarized bias current;
• creating a net spin polarization;
• creating a spin accumulation;
• creating spin polarized current flowing through surface states;
• detecting directly electrically the spin accumulation;
• utilizing the second contact to detect the spin polarization;
• wherein the second contact is magnetized and wherein the magnetization of the contact determines the spin detection axis;
• detecting electrically as a voltage a projection of the topological insulator spin polarization onto the spin detection axis;
• and
• utilizing the spin polarized surface states for spintronic/electronic applications.