Spin- and Valley Polarized Electron Layers

Description

Charge carriers in semiconductors can have a ‘valley’ degree of freedom, τ. Limited to discrete values (like spin), it can be manipulated by applying mechanical strain. This opens the prospect of valleytronics applications: In addition to the charges, the pseudospin corresponding to a valley’s population is employed for transporting further information. Most promising is to invoke both, τ and the conventional spin σ. We extend the linear response theory for partially spin-polarized electron layers to four-fold degenerate spin-valley systems. There, external electric, magnetic, and mechanical perturbations can independently influence the charge-, spin-, and valley-density, respectively. Using the Random Phase Approximation (RPA), we derive all partial and cross-correlation re- sponse functions. Their imaginary parts reflect the possible excitations of the system and show a rich structure, depending on momentum transfer ħq and energy transfer ħω. In particular, we find a region, where the system is totally non-responsive to applied magnetic fields and mechanical pertur- bations, similar to the magnetic antiresonance predicted in [1] for partially spin polarized systems. [1] D. Kreil, R. Hobbiger, J.T. Drachta, H.M. Böhm, Physical Review B 92, 205426 (2015)

Period	12 Sept 2018
Event title	68th Annual Meeting of the Austrian Physical Society
Event type	Conference
Location	AustriaShow on map