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Finite-bias Cooper pair splitting
L Hofstetter1, S Csonka, A Baumgartner
1Department of Physics, University of Basel, Switzerland.
Physical Review Letters
|October 27, 2011
Summary
We demonstrate electrical control over nonlocal transport in a Cooper pair splitter, a key step for developing entangled electron sources. This research explores Cooper pair splitting (CPS) and elastic cotunneling in quantum dots.
Area of Science:
- Quantum physics
- Condensed matter physics
- Nanotechnology
Background:
- Superconductors coupled to quantum dots (QDs) enable the study of nonclassical current correlations.
- Cooper pair splitting (CPS) is a phenomenon where a Cooper pair splits into two electrons with opposite spins.
- Understanding CPS is crucial for developing solid-state sources of entangled electrons.
Purpose of the Study:
- To experimentally investigate the nonlocal electrical transport in a Cooper pair splitter.
- To demonstrate the electrical tunability of quantum dot levels and their effect on Cooper pair splitting.
- To explore the role of the energy dependence of the effective density of states in QDs on CPS and elastic cotunneling.
Main Methods:
- Fabrication of a Cooper pair splitter on an InAs nanowire with two parallel quantum dots.
- Applying a finite potential difference across one quantum dot while the other remains grounded.
- Measuring the nonlocal electrical transport and conductance through the device.
Main Results:
- Demonstrated nonlocal electrical transport can be tuned by electrical means.
- Showed the relevance of the energy dependence of the effective density of states in QDs for Cooper pair splitting and elastic cotunneling rates.
- Established experimental tools for understanding and developing CPS-based entangled electron sources.
Conclusions:
- Electrical tunability of quantum dot levels offers a method to control Cooper pair splitting.
- The energy dependence of the QD density of states significantly impacts CPS and elastic cotunneling.
- This work provides essential experimental insights for advancing solid-state entangled electron sources.
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