Millisecond spin relaxation times of distinct electron and hole subensembles in MA$_x$FA$_{1-x}$PbI$_3$ perovskite crystals

TL;DR

This study demonstrates millisecond-scale spin relaxation times for electrons and holes in mixed-cation perovskite crystals, highlighting their potential for long-lived spin states in quantum information processing.

Contribution

The paper reports the first measurement of millisecond spin relaxation times in mixed-cation perovskite single crystals, revealing diverse spin subensembles and hyperfine interactions.

Findings

Multiple spin subensembles with distinct g-factors were resolved.

Spin relaxation times reach up to 2 ms at cryogenic temperatures.

Hyperfine interactions and carrier hopping influence spin relaxation dynamics.

Abstract

The unique combination of outstanding optical quality and attractive spin properties opens new avenues for optical spin control in hybrid organic-inorganic perovskite semiconductors. Using the optically detected magnetic resonance technique, we study the spins of electrons and holes in mixed-cation MA$_x$FA$_{1-x}$PbI$_3$ single crystals with $x = 0.4$ and 0.8. Multiple distinct spin subensembles with $g$-factors spanning from 2.9 to 3.6 for electrons and from 0.5 to 1.2 for holes are resolved, revealing diverse localization environments. We measure the longitudinal spin relaxation times, $T_1$, reaching 2 ms and remaining in the $\mu$s range even for weakly localized carriers at the cryogenic temperature of 1.6 K. The magnetic-field dependence of $T_1$ is dominated by the random nuclear (Overhauser) fields with strengths of $\sim 0.4-0.8$ mT for electrons and $\sim 4-12$ mT for holes, corresponding to $\mu$s-long correlation times of the hyperfine field determined by carrier hopping between shallow localization sites. The temperature dependence of $T_1$ reveals a weak localization potential of the charge carriers and shows a correlation between $T_1$ and the inhomogeneity of the spin ensemble. These results establish mixed-A-site perovskite single crystals as a promising solid-state platform with long-lived spin states for quantum information applications.