Magnetic nanohole superlattices
A magnetic material is disclosed including a two-dimensional array of carbon atoms and a two-dimensional array of nanoholes patterned in the two-dimensional array of carbon atoms. The magnetic material has long-range magnetic ordering at a temperature below a critical temperature Tc.
1. A magnetic material comprising:
a two-dimensional array of carbon atoms; and
a two-dimensional array of nanoholes patterned in said two-dimensional array of carbon atoms,
wherein said magnetic material has long-range magnetic ordering at a temperature below a critical temperature Tc.
2. The magnetic material of claim 1 , wherein Tc is greater than 298° K.
3. The magnetic material of claim 2 , wherein Tc depends on a structural property of the two-dimensional array of nanoholes.
4. The magnetic material of claim 3 , wherein the two-dimensional array of carbon atoms consist of an open hexagonal array.
5. The magnetic material of claim 4 , wherein the two-dimensional array of nanoholes comprises an array of nanoholes with edges having a zigzag configuration.
6. The magnetic material of claim 2 , wherein the long-range magnetic ordering is ferromagnetic ordering.
7. The magnetic material of claim 2 , wherein the long-range magnetic ordering is anti-ferromagnetic ordering.
8. The magnetic material of claim 5 , wherein the two-dimensional array of nanoholes comprises a first sublattice of nanoholes and a second sublattice of nanoholes.
9. The magnetic material of claim 8 , wherein the nanoholes of the first sublattice are arranged in a parallel configuration with respect to the nanoholes of the second sublattice.
10. The magnetic material of claim 8 , wherein the nanoholes of the first sublattice are arranged in an anti-parallel configuration with respect to the nanoholes of the second sublattice.
11. The magnetic material of claim 2 , wherein the array of nanoholes comprises at least one from the group of: a triangular shaped nanohole, a rhombus shaped nanohole, and a hexagonal nanohole.
12. The magnetic material of claim 2 , wherein the array of nanoholes comprises a nanohole having a characteristic size of about 50 nm or less.
13. The magnetic material of claim 2 , wherein the array of nanoholes comprises a nanohole having a characteristic size of about 100 nm or less.
14. The magnetic material of claim 2 , wherein the array of nanoholes comprises a nanohole having a characteristic size of about 500 nm or less.
15. The magnetic material of claim 2 , wherein the array of nanoholes comprises a nanohole having a characteristic size of about 1000 nm or less.
16. The magnetic material of claim 2 , wherein the array of nanoholes comprises a nanohole having a characteristic size of about 5000 nm or less.
17. The magnetic material of claim 2 , wherein the array of nanoholes has a density greater than about 10^-4 nanoholes per nm 2 .
18. The magnetic material of claim 2 , wherein the array of nanoholes has a density within the range of about 10^-8 nanoholes per nm 2 to about 10^-2 nanoholes per nm 2 .
19. A semiconductor material comprising:
a two-dimensional array of carbon atoms; and
a two-dimensional array of nanoholes patterned in said two-dimensional array of carbon atoms,
wherein said semiconductor material has a semiconductor bandgap Δ.
20. The semiconductor material of claim 19 , wherein bandgap Δ depends on a structural property of the two-dimensional array of nanoholes.
21. The semiconductor material of claim 19 , wherein the two-dimensional array of carbon atoms consists of an open hexagonal array.
22. The semiconductor material of claim 21 , wherein the two-dimensional array of nanoholes comprises an array of nanoholes with edges having an armchair configuration.
23. The semiconductor material of claim 22 , wherein the array of nanoholes consists of an array of triangular or rhombus shaped nanoholes.
24. The semiconductor material of claim 19 , wherein 1 meV≦Δ≦20 meV.
25. The semiconductor material of claim 19 , wherein 1 meV≦Δ≦2 eV.
26. A diluted magnetic semiconductor comprising:
a two-dimensional array of carbon atoms;
a two-dimensional array of a first type of nanoholes patterned in said two-dimensional array of carbon atoms; and
a two-dimensional array of a second type of nanoholes patterned in said two-dimensional array of carbon atoms,
wherein said diluted magnetic semiconductor material has a semiconductor bandgap Δ, and
wherein said diluted magnetic semiconductor has long-range magnetic ordering at a temperature below a critical temperature Tc.
27. The diluted magnetic semiconductor of claim 26 , wherein Tc is greater than 298° K.
28. The diluted magnetic semiconductor of claim 27 , wherein the two-dimensional array of the first type of nanoholes consists of nanoholes having intra-nanohole magnetic ordering.
29. The diluted magnetic semiconductor of claim 28 , wherein Tc depends on a structural property of the two-dimensional array of the first type of nanoholes.
30. The diluted magnetic semiconductor of claim 29 , wherein the bandgap Δ depends on a structural property of the two-dimensional array of the second type of nanoholes.
31. The diluted magnetic semiconductor of claim 30 , wherein the two-dimensional array of carbon atoms consists of an open hexagonal array.
32. The diluted magnetic semiconductor of claim 31 , wherein the two-dimensional array of the first type nanoholes comprises an array of nanoholes each with edges having a zigzag configuration.
33. The diluted magnetic semiconductor of claim 32 , wherein the two-dimensional array of the second type nanoholes comprises an array of nanoholes each with edges having an armchair configuration.
34. The diluted magnetic semiconductor of claim 27 , wherein the long-range magnetic ordering is ferromagnetic ordering.
35. The diluted magnetic semiconductor of claim 27 , wherein the long-range magnetic ordering is anti ferromagnetic ordering.
36. The diluted magnetic semiconductor of claim 33 , wherein the array of the second type of nanoholes consists of an array of rhombus shaped or hexagonal shaped nanoholes.
37. The diluted magnetic semiconductor of claim 27 , wherein 1 meV≦Δ≦20meV.
38. The diluted magnetic semiconductor of claim 27 , wherein 500 meV≦Δ≦2000 meV.
39. A magnetic information storage media comprising:
a two-dimensional array of carbon atoms, said array comprising a plurality of magnetic nanostructures, each of said nanostructures being in one of least two available magnetic states, said at least two available magnetic states comprising:
a first magnetic state associated with a first memory state; and
a second magnetic state associated with a second memory state.
40. The magnetic information storage media of claim 39 , wherein the plurality of magnetic nanostructures comprises a plurality of nanoholes.
41. The magnetic information storage media of claim 40 , wherein, for each of the plurality of nanoholes, the first magnetic state is a state of intra-nanohole antiferromagnetic ordering and the second magnetic state is a state of intra-nanohole ferromagnetic ordering.
42. The magnetic information storage media of claim 41 , further comprising a reader unit adapted to read out the magnetic state of one or more of the plurality of magnetic nanostructures.
43. The magnetic storage information media of claim 39 , further comprising a write unit adapted to change the magnetic state of one or more of the plurality of magnetic nanostructures.
44. The magnetic information storage media of claim 40 , wherein the plurality of nanoholes comprises a nanohole having a characteristic size of about 50 nm or less.
45. The magnetic information storage media of claim 40 , wherein the plurality of nanoholes comprises a nanohole having a characteristic size in the range of about 50 nm to about 1000 nm.
46. The magnetic information storage media of claim 40 , wherein the plurality of nanoholes has an average density greater than about 10^-4 nanoholes per nm 2 .
47. The magnetic information storage media of claim 39 , wherein the first and second magnetic states are stable over a timescale greater than 1 hour.
48. An apparatus comprising
a detector comprising:
a semiconductor material comprising:
a two-dimensional array of carbon atoms; and
a two-dimensional array of nanoholes patterned in said two-dimensional array of carbon atoms,
wherein said semiconductor material has a semiconductor bandgap Δ, and
wherein the detector is adapted to produce a signal in response to electromagnetic radiation incident on the semiconductor material.
49. The apparatus of claim 48 , wherein the bandgap Δ depends on a structural property of the two-dimensional array of nanoholes.
50. The apparatus of claim 48 , wherein the detector is adapted to produce a signal in response to electromagnetic radiation incident on the semiconductor material, said radiation having a frequency corresponding to a photon energy at or near the bandgap Δ.
51. The apparatus of claim 50 , wherein 1 meV≦Δ≦20 meV, and the detector is adapted to produce a signal in response to electromagnetic radiation incident on the semiconductor material, said radiation having a frequency in the terahertz or far infrared radiation.
52. A magnetic material comprising:
a plurality of layers, each comprising a two-dimensional array of carbon atoms; and
a two-dimensional array of nanoholes patterned in at least one of the said two-dimensional array of carbon atoms,
wherein said magnetic material has long-range magnetic ordering at a temperature below a critical temperature Tc.
53. The magnetic material of claim 52 , wherein Tc is greater than 298° K.
54. The magnetic material of claim 53 , wherein Tc depends on a structural property of the two-dimensional array of nanoholes.
55. The magnetic material of claim 54 , wherein the plurality of layers comprises a top layer and one or more underlying layers, and the two-dimensional array of nanoholes is patterned in the top layer.
56. The magnetic material of claim 55 , wherein the two-dimensional array of nanoholes comprises an array of nanoholes with edges having a zigzag configuration.
57. The magnetic material of claim 56 , wherein the one or more underlying layers comprise bulk carbon.
58. A magnetic material comprising:
a plurality of layers stacked along a vertical direction, each layer comprising a two-dimensional array of carbon atoms; and
a two-dimensional array of nanotunnels patterned substantially vertically through the plurality of layers,
wherein said magnetic material has long-range magnetic ordering at a temperature below a critical temperature Tc.
59. The magnetic material of claim 58 , wherein Tc is greater than 298° K.
60. The magnetic material of claim 59 , wherein Tc depends on a structural property of the two-dimensional array of nanotunnels.
61. The magnetic material of claim 60 , wherein the two-dimensional array of nanoholes comprises an array of nanotunnels with edges having a zigzag configuration.
62. The magnetic material of claim 56 , wherein the plurality of layers comprises bulk carbon.
63. An apparatus comprising
a detector material comprising:
a two-dimensional array of carbon atoms; and
a two-dimensional array of nanoholes patterned in said two-dimensional array of carbon atoms; and
a monitor which produces a signal indicative of a change in a physical property of the material in response to a change in a chemical environment of the detector material.
64. The apparatus of claim 63 , wherein the monitor produces a signal indicative of a change in a transport property of the detector material in response to adsorption of molecules from the chemical environment by the two-dimensional array of nanoholes.