Manipulation of Spin Splitting in Two-Dimensional Lead Bromide Perovskite Rashba Piezoelectrics

In
this work, a two-dimensional perovskite Rashba piezoelectrics
(TPRP) is proposed by a density functional theory study. The Rashba
spin splitting in TPRP is optimized via the dipole moment of A-site
organic cations and the atom displacement in inorganic [PbBr6]2– octahedrons. The Rashba spin splitting energy
and the corresponding parameter (αR) of unstrained
(ATHP)2PbBr4 TPRP are calculated as 41 meV and
0.65 eV·Å, respectively. This value should be the highest
for any Br-based lead halide perovskites to the best of our knowledge.
In addition, the value of αR, responsible for the
piezoelectric potential, is further tuned from 0.41 to 0.81 eV·Å
via adjusting the local polarization by applying a strain from +0.01
to −0.01 along the c axis.