Hole-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi mathvariant="normal">Cr</mml:mi><mml:mo>+</mml:mo></mml:msup></mml:math> nanomagnet in a semiconductor quantum dot

Abstract

Here, the authors show that the negatively charged Cr${}^{+}$ ion, an excited state of Cr in II-VI semiconductors, can be stable when inserted in a CdTe quantum dot. The Cr${}^{+}$ attracts a hole and forms a hole-Cr${}^{+}$ spin complex with a ferromagnetic coupling. The resulting nanomagnet can be controlled optically. The ferromagnetic ground states, with total spin ${M}_{z}$ = \ifmmode\pm\else\textpm\fi{}4, are prepared by resonant optical pumping and a spin memory in the 20 \textmu{}s range is obtained at 4.2 K and zero magnetic field.

Topics & Concepts