Epitaxial superconducting devices and method of forming same
View Patent ↗Superconducting regions formed with a crystal provide highly doped regions of acceptor atoms. These superconducting regions are used to provide superconducting devices wherein non-epitaxial interfaces have been eliminated. A method is provided to highly doped regions of a crystal to form the superconducting regions and devices. By forming the superconducting regions within the crystal non-epitaxial interfaces are eliminated.
1. A superconducting device comprising:
a crystal;
a portion of said crystal highly-doped with acceptor atoms, providing a superconducting region, the superconducting region including a plurality of monolayers, wherein fewer than all of the monolayers are doped;
wherein the superconducting region is surrounded by the crystal; and
wherein an interface between said crystal and said superconducting region is epitaxial.
2. The device of claim 1 , wherein said crystal is silicon.
3. The device of claim 1 , wherein said crystal is germanium.
4. The device of claim 1 , wherein said crystal is diamond.
5. The device of claim 1 , wherein the number of monolayers provided by said superconducting region is determined by N total =(N 1 −1)k+1, where k identifies the frequency of doping of the monolayers, N 1 identifies the number of monolayers which have been doped, and is provided by
N
1
=
a
2
n
C
(
4
-
d
B
-
ak
)
(
C
2
+
T
C
2
)
a
3
k
n
C
(
C
2
+
T
C
2
)
-
8
C
2
r
D
,
and a is the lattice constant of the crystal, T c is the critical superconducting temperature sought, r D is the doping rate per layer, d B is the effective electron or hole density region in the highly-doped region, n c is the minimum impurity density required for superconductivity, and C is a material constant for said crystal.
6. The device of claim 1 :
wherein the device includes first and second superconducting regions; and
wherein said first and second superconducting regions are spaced to form a capacitance.
7. The device of claim 1 :
wherein the device includes first and second superconducting regions; and
a junction positioned between said first and second superconducting regions to provide a Josephson junction.
8. The device of claim 7 , wherein said junction is provided by a portion of said crystal forming an insulating region, said superconducting regions are separated by a distance such that quantum tunneling can occur between said two superconducting regions through said insulating region.
9. The device of claim 7 , wherein said junction is provided by a weak link junction.
10. The device of claim 1 , further comprising:
a top gate; and
wherein said top gate provides modulation of a density of carriers in said superconducting region.
11. The device of claim 8 , further comprising:
a top gate; and
wherein said top gate provides modulation of a the carriers in said junction.
12. The device of claim 1 :
wherein the device includes first and second superconducting regions and a junction and said device provides a qubit.
13. The device of claim 1 :
wherein the device includes first and second superconductor regions;
a junction positioned between said first and second superconducting regions; and
wherein said first and second superconducting regions form a loop and said device functions as a SQUID.
14. The device of claim 1 :
wherein said superconducting region is in communication with a superconducting resonator circuit to provide a particle detector.
15. The device of claim 14 , further comprising:
a top gate; and
wherein said top gate provides modulation of a density of carriers in said superconducting region, thereby providing an adjustable superconducting energy gap of the particle detector.
16. The device of claim 1 , further comprising an abrupt transition region, wherein said transition region is approximately one monolayer thick.