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Published on: June 28, 2018
Polarization in a Rashba strip coupled with a spiral spin density wave
1Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China. zyzhang@nju.edu.cn
Summary
The magnetoelectric effect in a Rashba strip coupled to a spiral spin density wave (SDW) can be switched by gate voltage. Polarization direction depends on helix axis and wavevector, influenced by spin-orbit and exchange couplings.
Area of Science:
- Condensed matter physics
- Spintronics
- Materials science
Background:
- The magnetoelectric effect allows control of electric polarization with magnetic fields and vice versa.
- Rashba spin-orbit coupling in low-dimensional systems is crucial for spintronic applications.
- Spiral spin density waves (SDWs) exhibit unique magnetic ordering relevant to exotic electronic properties.
Purpose of the Study:
- To investigate the magnetoelectric effect in a Rashba strip coupled to an SDW.
- To understand the influence of gate voltage, helix axis, wavevector, Rashba spin-orbit coupling, and exchange coupling on induced polarization.
- To identify key factors governing polarization behavior and its potential for switching.
Main Methods:
- Theoretical study of a coupled Rashba strip and SDW system.
- Analysis of polarization behavior as a function of various physical parameters.
- Identification of contributions from eigenstates near von Hove singularities.
Main Results:
- Induced polarization is perpendicular to the plane defined by the helix axis and SDW wavevector.
- Polarization is switchable via gate voltage and reverses with changes in helix axis or wavevector.
- Averaged polarization oscillates with increasing Rashba spin-orbit coupling and shows non-monotonic behavior with exchange coupling.
Conclusions:
- The magnetoelectric effect in this system is tunable and switchable, offering potential for novel electronic devices.
- Eigenstates near von Hove singularities significantly contribute to the polarization.
- Spin precession length is a critical parameter for understanding size effects on polarization.
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