Spatial imaging and mechanical control of spin coherence in strained GaAs epilayers

Abstract

The effect of uniaxial tensile strain on spin coherence in n-type GaAs epilayers is probed using time-resolved Kerr rotation, photoluminescence, and optically-detected nuclear magnetic resonance spectroscopies. The bandgap, electron spin lifetime, electron g-factor, and nuclear quadrupole splitting are simultaneously imaged over millimeter scale areas of the epilayers for continuously varying values of strain. All-optical nuclear magnetic resonance techniques allow access to the strain induced nuclear quadrupolar resonance splitting in field regimes not easily addressable using conventional optically-detected nuclear magnetic resonance.

Spin dynamics in semiconductors

“…Usually the effect of electric field on spin relaxation is more pronounced at low temperature [110,372,527,548,568]. The spin lifetime can also be reduced by applying strain, which induces additional spin-orbit coupling [144,145,571,572]. It was found that 1/τ s ∼ 2 , where is the applied stress [572] when the strain-induced spin-orbit coupling dominates.…”

“…We now review the experimental studies on carrier spin relaxation at low temperature in the insulating regime. Many efforts have been devoted to the spin relaxation in n-GaAs at low temperature [4,39,144,321,497,[501][502][503]511,[514][515][516][517][518][519][520][521]. In one of the seminal works, by Kikkawa and Awschalom [4], a surprisingly long spin lifetime (130 ns) was observed in n-GaAs, which sheds light on the possibility of semiconductor spintronics.…”

Role of strain on the coherent properties of GaAs excitons and biexcitons

“…5 Manipulation of strain may also lead to the development of polarization-entangled photon pairs through control of the relative size of the exciton and biexciton binding energies in quantum dot systems, 6 and provides a means to dynamically manipulate the spin-orbit interaction for possible spin-sensitive electronic devices. 7,8 For such applications, an accurate characterization of the influence of strain on the local and global optoelectronic properties in the semiconductor heterostructure is essential. Existing studies of strain in semiconductor systems have largely focused on its influence on the energetic locations of the heavy-hole (HH) and light-hole (LH) exciton resonances, detected using optical techniques such as photoluminescence, reflectivity and Raman scattering.…”

Transitions of epitaxially lifted-off bulk GaAs and GaAs/AlGaAs quantum well under thermal-induced compressive and tensile strain

“…In bulk and quantum well ͑QW͒ structures, strain is introduced through external mechanical application, [3][4][5][6][7] lattice mismatched epitaxial growth, [8][9][10] and by the difference in the thermal expansion coefficient of the substrate. In bulk and quantum well ͑QW͒ structures, strain is introduced through external mechanical application, [3][4][5][6][7] lattice mismatched epitaxial growth, [8][9][10] and by the difference in the thermal expansion coefficient of the substrate.…”