Dynamics of Spin Organization in Diluted Magnetic Semiconductors

Time-resolved magnetophotoluminescence studies of magnetic polaron dynamics in type-II quantum dots

“…If we assume strong hole localization due to alloy and spin disorder scattering, 55 our calculations suggest a large molecular field Bm (>20 tesla). If we make the additional assumption that the pulsed laser excitation resulted in an increase of the hole-Mn system effective temperature above the lattice temperature, our calculations describe adequately the behavior of sample 3 as shown in Fig.…”

Optical studies of zero-field magnetization of CdMnTe quantum dots: Influence of average size and composition of quantum dots

“…instability of EMPs) and the very rapid time decay of the spin alignment [10], this optically induced magnetization exists only at relatively low temperatures (< 6K). It is also important to note that even though a small magnetization was detected by a micro-SQUID magnetometer, no corresponding optical signature for the magnetization was observed, as the decay of the spin alignment has been found to be much faster than the exciton recombination time [12].…”

Direct Measurements of Magnetic Polarons in Cd1–xMnxSe Nanocrystals from Resonant Photoluminescence

“…As such, local spin-spin interactions can be greatly enhanced by strong quantum confinement, which compresses carrier wavefunctions to nanometer-scale volumes and therefore increases |ψ e,h (r)| 2 . The extent to which these exchange interactions can be enhanced and controlled via quantum confinement is an area of significant current interest and has recently been studied in a variety of magnetically-doped semiconductor nanostructures, including nanoribbons [12, 13], nanoplatelets [14], epitaxial quantum dots [14][15][16][18][19][20][21][22][23][24][25][26], and colloidal nanocrystals [1-8, 27, 28, 30].A particularly striking consequence of sp-d interactions in II-VI semiconductors is the formation of exciton magnetic polarons (EMPs), wherein the effective magnetic exchange field from a single photogenerated exciton -B ex -induces the collective and spontaneous ferromagnetic alignment of the magnetic dopants within its wavefunction envelope, generating a net local magnetization even in the absence of any applied field [31][32][33]. In turn, these aligned local moments act back on the exciton's spin, which lowers the exciton's energy, further localizes the exciton, and further stabilizes the polaron.…”

“…A particularly striking consequence of sp-d interactions in II-VI semiconductors is the formation of exciton magnetic polarons (EMPs), wherein the effective magnetic exchange field from a single photogenerated exciton -B ex -induces the collective and spontaneous ferromagnetic alignment of the magnetic dopants within its wavefunction envelope, generating a net local magnetization even in the absence of any applied field [31][32][33]. In turn, these aligned local moments act back on the exciton's spin, which lowers the exciton's energy, further localizes the exciton, and further stabilizes the polaron.…”