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Entropy Wave Instability in Dirac and Weyl Semimetals
P O Sukhachov1, E V Gorbar2,3, I A Shovkovy4,5
1Department of Physics, Yale University, New Haven, Connecticut 06520, USA.
Physical Review Letters
|November 5, 2021
Summary
Two hydrodynamic instabilities, Dyakonov-Shur and entropy wave, were found in relativisticlike systems. The entropy wave instability, linked to electron quasiparticles and energy currents, is tunable by system size and flow velocity.
Area of Science:
- Condensed matter physics
- Plasma physics
- Fluid dynamics
Background:
- Hydrodynamic instabilities are crucial in understanding electron transport in materials.
- Relativisticlike systems exhibit unique quantum phenomena.
- Dyakonov-Shur boundary conditions are essential for analyzing boundary effects in 2D electron systems.
Purpose of the Study:
- To analyze hydrodynamic instabilities in 2D and 3D relativisticlike systems under direct current.
- To investigate the role of temperature boundary conditions in these instabilities.
- To identify and characterize novel instabilities beyond the conventional Dyakonov-Shur instability.
Main Methods:
- Analysis of hydrodynamic equations in 2D and 3D systems.
- Application of Dyakonov-Shur boundary conditions.
- Inclusion of a temperature boundary condition.
- Investigation of electron quasiparticle behavior and energy currents.
Main Results:
- Identified two types of hydrodynamic instabilities: Dyakonov-Shur instability and entropy wave instability.
- Entropy wave instability arises from the relativisticlike nature of electron quasiparticles and energy currents.
- These instabilities occur for opposite directions of fluid flow.
- Dyakonov-Shur instability depends on plasma frequency (3D) or system size (2D).
- Entropy wave instability frequency is tunable by system size and flow velocity.
Conclusions:
- Entropy wave instability is a new phenomenon in relativisticlike systems, distinct from plasmon instabilities.
- The findings highlight the importance of electron quasiparticle properties and energy transport in driving instabilities.
- Tunability of entropy wave instability offers potential for controlling electron dynamics in novel electronic devices.
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