System and method of generating phonons
Systems and methods are disclosed for controlling nonequilibrium electron transport process and generating phonons in low dimensional materials. The systems can include a conductive sheet sandwiched between a first insulation layer and a second insulation layer; a first electrode conductively coupled to a first end of the conductive sheet; a second electrode conductively coupled to a second end of the conductive sheet; and a current source conductively coupled to the first electrode and the second electrode and configured to pass a current from the first electrode through the conductive sheet to the second electrode such that current generates a drift velocity of electrons in the conductive sheet that is greater than the speed of sound to generate phonons.
1. A system comprising:
a conductive sheet sandwiched between a first insulation layer and a second insulation layer;
a first electrode conductively coupled to a first end of the conductive sheet;
a second electrode conductively coupled to a second end of the conductive sheet; and
a current source conductively coupled to the first electrode and the second electrode and configured to pass a current from the first electrode through the conductive sheet to the second electrode such that the current generates a drift velocity of electrons in the conductive sheet that is greater than the speed of sound to generate phonons.
2. The system of claim 1 , wherein the conductive sheet comprises graphene.
3. The system of claim 1 , wherein the conductive sheet comprises a transition metal dichalcogenide.
4. The system of claim 1 , wherein the generated phonons have a frequency having an order of magnitude between 1 to 10 terahertz.
5. The system of claim 1 , wherein one or more of the first insulation layer or the second insulation layer comprise hexagonal boron nitride (hBN).
6. The system of claim 1 , wherein the mobility of the electrons in the conductive sheet is not less than 5 m 2 /Vs.
7. The system of claim 1 , further comprising a conductive top gate disposed on the second insulation layer opposite the conductive sheet, wherein a charge on the conductive top gate adjusts the frequency of the generated phonons.
8. The system of claim 1 , wherein the distance between the first electrode and the second electrode is not less than 1.5 microns.
9. The system of claim 1 , wherein the drift velocity of electrons in the conductive sheet is at least twice the speed of sound.
10. The system of claim 1 , wherein the current amplifies the generated phonons.
11. A method comprising:
disposing a conductive sheet between a first insulation layer and a second insulation layer;
connecting a first electrode to a first end of the conductive sheet;
connecting a second electrode to a second end of the conductive sheet;
connecting the first and second electrodes to a current source; and
applying, with the current source, a current from the first electrode through the conductive sheet to the second electrode such that the current generates a drift velocity of electrons in the conductive sheet that is greater than the speed of sound to generate phonons.
12. The method of claim 11 , wherein the conductive sheet comprises graphene.
13. The method of claim 11 , wherein the conductive sheet comprises a transition metal dichalcogenide.
14. The method of claim 11 , wherein the generated phonons have a frequency having an order of magnitude between 1 to 10 terahertz.
15. The method of claim 11 , wherein one or more of the first insulation layer or the second insulation layer comprise hexagonal boron nitride (hBN).
16. The method of claim 11 , wherein the mobility of the electrons in the conductive sheet is not less than 5 m 2 /Vs.
17. The method of claim 11 , further comprising:
forming a conductive top gate on the second insulation layer opposite the conductive sheet; and
adjusting a frequency of the generated phonons by altering a charge on the conductive top gate.
18. The method of claim 11 , wherein the distance between the first electrode and the second electrode is not less than 1.5 microns.
19. The method of claim 11 , wherein the drift velocity of electrons in the conductive sheet is at least twice the speed of sound.
20. The method of claim 11 , wherein the current amplifies the generated phonons.
21. A system comprising:
a conductive sheet;
a first electrode conductively coupled to a first end of the conductive sheet;
a second electrode conductively coupled to a second end of the conductive sheet; and
a current source conductively coupled to the first electrode and the second electrode and configured to pass a current from the first electrode through the conductive sheet to the second electrode such that current generates a drift velocity of electrons in the conductive sheet that is greater than the speed of sound to generate phonons.
22. The system of claim 21 , wherein the conductive sheet is suspended above a substrate.
23. The system of claim 21 , further comprising an insulator disposed on at least a portion of the conductive sheet.
24. The system of claim 21 , wherein the insulation layer comprises hexagonal boron nitride (hBN).
25. The system of claim 21 , wherein the conductive sheet comprises graphene.
26. The system of claim 21 , wherein the conductive sheet comprises a transition metal dichalcogenide.