Beyond the ordinary acoustoelectric effect: Superluminal phenomena in the acoustic realm and phonon-mediated Bloch gain

0566503 - FZÚ 2023 RIV US eng J - Journal Article
Apostolakis, Apostolos - Balanov, A.G. - Kusmartsev, F.V. - Alekseev, K.N.
Beyond the ordinary acoustoelectric effect: Superluminal phenomena in the acoustic realm and phonon-mediated Bloch gain.
Physical Review B. Roč. 106, č. 1 (2022), č. článku 014312. ISSN 2469-9950. E-ISSN 2469-9969
R&D Projects: GA ČR GA19-03765S
Institutional support: RVO:68378271
Keywords : superluminal effects * nonlinear dynamics * acoustic phonons * anomalous Doppler effect * Cherenkov effect * Bloch gain * superlattices * quantum transport
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 3.7, year: 2022
Method of publishing: Limited access
https://doi.org/10.1103/PhysRevB.106.014312

Interaction of acoustic phonons and fast-moving carriers in semiconductor heterostructures can be accompanied by electron-phonon instabilities that cause ordinary and induced Cherenkov effects. Our study shows that other supersonic phenomena, beyond the Cherenkov instability, are possible for nonequilibrium charge transport in the miniband semiconductor superlattices (SLs) driven by an acoustic plane wave. We find the conditions for the onset of dynamical instabilities which are caused by the emission of specific SL phonons by supersonic electrons, and their back action on the electrons. Notably, the underlying radiation mechanism is connected either to normal or anomalous Doppler effects in full accordance with the Ginzburg-Frank-Tamm theory. We demonstrate that the discovered superluminal Doppler phenomena can be utilized for tunable broadband amplification and generation of GHz-THz electromagnetic waves, which creates a ground for the development of novel phononic devices.
Permanent Link: https://hdl.handle.net/11104/0337820