Nonlinear transport and noise thermometry in quasi-classical ballistic point contacts
| Autor: | Tikhonov, E. S., Melnikov, M. Yu., Shovkun, D. V., Sorba, L., Biasiol, G., Khrapai, V. S. |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Physical Review B 90, 161405(R) (2014) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.90.161405 |
| Popis: | We study nonlinear transport and non-equilibrium current noise in quasi-classical point contacts (PCs) defined in a low-density high-quality two-dimensional electron system in GaAs. At not too high bias voltages $V$ across the PC the noise temperature is determined by a Joule heat power and almost independent on the PC resistance that can be associated with a self-heating of the electronic system. This commonly accepted scenario breaks down at increasing $V$, where we observe extra noise accompanied by a strong decrease of the PC's differential resistance. The spectral density of the extra noise is roughly proportional to the nonlinear current contribution in the PC $\delta S\approx2F^*|e\delta I|\sim V^2$ with the effective Fano factor $F^*<1$, indicating that a random scattering process is involved. A small perpendicular magnetic field is found to suppress both $\delta I$ and $\delta S$. Our observations are consistent with a concept of a drag-like mechanism of the nonlinear transport mediated by electron-electron scattering in the leads of quasi-classical PCs. Comment: to appear in PRB |
| Databáze: | arXiv |
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