Scalable quantum computer architecture with coupled donor-quantum dot qubits
A quantum bit computing architecture includes a plurality of single spin memory donor atoms embedded in a semiconductor layer, a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, wherein a first voltage applied across at least one pair of the aligned quantum dot and donor atom controls a donor-quantum dot coupling. A method of performing quantum computing in a scalable architecture quantum computing apparatus includes arranging a pattern of single spin memory donor atoms in a semiconductor layer, forming a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, applying a first voltage across at least one aligned pair of a quantum dot and donor atom to control a donor-quantum dot coupling, and applying a second voltage between one or more quantum dots to control a Heisenberg exchange J coupling between quantum dots and to cause transport of a single spin polarized electron between quantum dots.
1. A quantum bit computing apparatus comprising:
a semiconductor layer;
a plurality of donor atoms embedded in the semiconductor layer, the plurality of donor atoms being single spin memory donor atoms; and
a plurality of quantum dots arranged with the semiconductor layer, each of the plurality of quantum dots aligned with each of plurality of donor atoms to form a plurality of pairs, each pair including a donor atom and a quantum dot, wherein a first voltage is configured to be applied across a first pair of the plurality of pairs to control a coupling between a first donor atom and a first quantum dot of the first pair.
2. The apparatus of claim 1 , further comprising:
a first dielectric layer disposed on a first surface of the semiconductor layer; and
a plurality of top gate electrodes arranged on the first dielectric layer, each the plurality of top gate electrodes defining a location of each of the plurality of pairs.
3. The apparatus of claim 2 , further comprising:
a second dielectric layer disposed on a second surface of the semiconductor layer; and
one or more back gate electrodes arranged on the second dielectric layer.
4. The apparatus of claim 3 , further comprising a substrate, wherein the one or more back gate electrodes, the second dielectric layer, the semiconductor layer, the first dielectric layer, and the plurality of top electrodes are formed on the substrate.
5. The apparatus of claim 3 , wherein the first voltage is configured to be applied across a first back gate electrode of the one or more back gate electrodes and a first top gate electrode of the plurality of top gate electrodes, wherein the first back gate electrode and the top gate electrode are associated with the first pair.
6. The apparatus of claim 1 , wherein a donor atom-quantum dot spin exchange occurs when the first voltage has a first polarity.
7. The apparatus of claim 6 , wherein a donor atom-quantum dot spin exchange does not occur when the first voltage has a second polarity opposite to the first polarity.
8. The apparatus of claim 3 , wherein a second voltage applied is configured to be applied between one or more top gate electrodes, and wherein the second voltage is configured to control a Heisenberg exchange J coupling between quantum dots of the plurality of quantum dots or configured to control transport of a single spin polarized electron between quantum dots of the plurality of quantum dots.
9. The apparatus of claim 1 , wherein the semiconductor layer is an epitaxially grown semiconductor layer.
10. The apparatus of claim 1 , wherein the semiconductor layer is at least one of 28 Si and a Si—Ge heterostructure.
11. The apparatus of claim 1 , wherein the plurality of donor atoms comprises at least one of phosphorous, arsenic, antimony, and bismuth.
12. The apparatus of claim 1 , wherein a separation between a donor atom of the plurality of donor atoms and a quantum dot of the plurality of quantum dots is about 10 nanometers to 30 nanometers.
13. The apparatus of claim 1 , wherein each of the plurality of donor atoms are spaced about 100 nanometers or more apart.
14. The apparatus of claim 2 , wherein the first dielectric layer is approximately 2 nanometers to 10 nanometers thick.
15. The apparatus of claim 2 , wherein the first dielectric layer is at least one of SiO 2 and Al 2 O 3 .
16. The apparatus of claim 3 , wherein the second dielectric layer is approximately 10 nanometers to 100 nanometers thick.
17. The apparatus of claim 3 , wherein the second dielectric layer is at least one of SiO 2 and Al 2 O 3 .