PUMP PROBE STUDIES OF SPIN DYNAMICS IN THE 2D PEROVSKITE BUTYLAMMONIUM METHYLAMMONIUM LEAD IODIDE

Abstract

Halide perovskites have emerged as a promising class of materials for spintronic applications due to their large spin-orbit coupling and Rashba splitting. In this thesis, circularly polarized pump-probe spectroscopy was used to study the spin dynamics and relaxation mechanisms in the 2D perovskite butylammonium methylammonium lead iodide, BA2MAPb2I7. The spin lifetime and initial degree of spin polarization was found to be 10 ps and 80% respectively for above bandgap laser excitation at room temperature. Spin lifetime and degree of spin polarization increased with laser fluence and decreased with excess energy above bandgap, indicating the dominant spin relaxation mechanism at room temperature is D'yakonov-Perel'. A strong reduction in the spin polarization was observed in the low-temperature phase, attributed to subpicosecond electron spin relaxation, with a residual spin lifetime of 100 ps at 10 K attributed to holes. These results will help assess the viability of 2D perovskites for applications in spintronics.