Anisotropic spin dynamics of confined electrons in CdTe/ZnTe quantum structures

Abstract

We have studied the spin dynamics of confined electrons in an ultrathin CdTe/ZnTe quantum well and self-assembled quantum dots by time-resolved Kerr-rotation technique. The dependence of the spin-precession frequency on the magnetic field direction shows the anisotropy of the g-factor tensor, which is the opposite of the usual quantum wells with moderate widths. The geometrical anisotropy of the confinement also affects the initial orientation of the electron spins created optically, as revealed clearly with the use of oblique-incidence pump pulses.

Excitation energy dependence of initial phase shift in Kerr rotation of resident electron spin polarization in a CdTe single quantum well

“…The value for of this sample was found in our previous study . Since the pump and probe beams are in the x – z plane, that is, orthogonal to the spin precession plane ( y – z plane), any extrinsic initial phase shifts of the electron spin precession, for instance, due to an oblique incidence of the pump pulse , do not arise.…”

Structural, electronic and optical properties of ZnX and CdX compounds (X=Se, Te and S) under hydrostatic pressure

“…Moreover they appear to be promising candidates for many technological applications [17], such as blue laser fabrication techniques, optoelectronic devices operating in the visible light range and in UV photodetectors and modulated hetero structures, light emitting diode, reflector, dielectric filter, optical switching devices, optical wave guides, high density optical memories, solar cells, photovoltaic cells [18], etc. There have been considerable applications in the area of nanostructures, such as nano-wires, thin films, quantum dot lasers as well as those related to passivating the surface of other materials to create confined particles [19][20][21], etc. There have been many empirical and ab initio calculations of the electronic and optical properties for these compounds [22][23][24][25][26][27][28][29][30][31][32].…”

Exciton spin dynamics in CdTe/ZnTe quantum structures

“…We can expect the variation of the character of spin dynamics, from an exciton to an isolated electron, with increase of temperature in these systems. Previously, we observed such transitional temperature behavior of the spin dynamics using the time‐resolved Kerr rotation (TRKR) measurement 4. At temperatures lower than about 100 K, the TRKR signal is dominated by simple decay within 20 ps, which does not show the damped oscillation expected for the electron‐spin precession in the transverse magnetic field.…”

“…Two samples are grown by molecular‐beam epitaxy: (a) a CdTe/ZnTe single QW with 2 monolayer (ML) well width and (b) self‐assembled QDs in which nominally 3.5 ML CdTe was deposited. They are the same samples as those used in the previous study 4. We will refer to the sample (a) as QW and the sample (b) as QD below.…”