Giant Spin Splitting in Chiral Perovskites Based on Local Electrical Field Engineering

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Chemistry

Background:

• Chiral hybrid organic-inorganic perovskites (chiral HOIPs) exhibit promising spintronic and spin-optoelectronic properties.
• Theoretical investigations into the spin physics of chiral HOIPs remain limited.

Purpose of the Study:

• To theoretically investigate the spin characteristics of Pb-I based chiral HOIPs.
• To propose and evaluate a molecular engineering strategy for enhancing spin splitting in chiral HOIPs.

Main Methods:

• First-principles calculations were employed to study spin properties.
• A k·p model Hamiltonian, informed by symmetry arguments, was utilized.
• The impact of halogen substitution on molecular electrostatic potential was analyzed.

Main Results:

• Spin splitting in chiral HOIPs was significantly enhanced by halogen substitution.
• Spin splitting increased from 13 meV to 73, 90, and 105 meV with F, Cl, and Br substitution, respectively.
• Halogen substitution was found to strengthen the local electric field and distort the PbI6 octahedron.

Conclusions:

• Molecular engineering via halogen substitution offers an effective route to tune spin splitting in chiral HOIPs.
• This approach provides insights for designing novel spintronic materials.