Transient and steady state magneto-optical studies of the CsPbBr3 crystal

We have studied the magneto-optical properties of photoexcitations in $\mathrm{CsPb}{\mathrm{Br}}₃$ single crystal using the technique of picosecond time-resolved quantum beatings (QBs) in the circularly polarized photoinduced reflection as well as steady state magnetocircular dichroism (MCD) in $\mathrm{CsPb}{\mathrm{Br}}₃$ film. In the Voigt geometry at magnetic field strength $B$ > 0, we observed fast and slow QB oscillations that we attribute to the Larmor precession frequency of electrons and holes, respectively. From the linear frequency dependence on $B$, we extract the carrier anisotropic Land\'e $g$ factors for applied B along [010] and [001]; for electrons $|{g}_[001]^{\mathrm{e}}|=1.95\ifmmode\pm\else\textpm\fi{}0.04$ and $|{g}_[010]^{\mathrm{e}}|=1.82\ifmmode\pm\else\textpm\fi{}0.04$, whereas for holes $|{g}_[001]^{\mathrm{h}}|=0.69\ifmmode\pm\else\textpm\fi{}0.02$ and $|{g}_[010]^{\mathrm{h}}|=0.76\ifmmode\pm\else\textpm\fi{}0.02$. These values are in excellent agreement with a k\ifmmode\cdot\else\textperiodcentered\fi{}p model calculation applied to $\mathrm{CsPb}{\mathrm{Br}}₃$. Surprisingly, at $B=0$, we still observed QB oscillation of \ensuremath{\sim}500 MHz that we interpret as due to the Overhauser field that originates from the spin-aligned nuclei caused by the Knight field. From the measured MCD spectrum vs $B$, we obtained the $g$ factor of the bright excitons ${g}_{\mathrm{ex}}=2.18\ifmmode\pm\else\textpm\fi{}0.08$ showing that the $g$ value of holes in $\mathrm{CsPb}{\mathrm{Br}}₃$ is positive. We also measured the temperature and magnetic field dependencies of the electron and hole spin dephasing times which support the Elliot-Yafet spin-relaxation mechanism.