Deterministic Structural Distortion in Mn²⁺-Doped Layered Hybrid Lead Bromide Perovskite Single Crystals

Area of Science:

• Materials Science
• Solid-State Physics
• Semiconductor Physics

Background:

• Dilute magnetic doping in wide-bandgap semiconductors offers potential for novel optical and spintronic properties.
• Understanding dopant-induced structural changes in high-quality single crystals is crucial but underexplored.

Purpose of the Study:

• To investigate the structural modifications in Mn2+-doped (BA)2PbBr4 single crystals as a function of Mn2+ concentration.
• To elucidate the driving forces behind dopant-induced structural distortion and confirm Mn2+ incorporation.

Main Methods:

• Synthesis of Mn2+-doped (BA)2PbBr4 single crystals with controlled Mn2+ content.
• Structural analysis using X-ray diffraction and microscopy to quantify crystal deformation.
• Density functional theory (DFT) calculations to model the thermodynamic stability.
• Photoluminescence spectroscopy, electron paramagnetic resonance (EPR), and superconducting quantum interference device (SQUID) measurements to confirm Mn2+ incorporation and properties.

Main Results:

• Significant crystal deformation observed, including in-plane shear distortion (up to ~6°) and out-of-plane contraction (9.7%) at 4.95% Mn2+ concentration.
• DFT calculations confirm that structural distortion is driven by a thermodynamic energy gain.
• Successful Mn2+ incorporation confirmed by characteristic 600 nm emission, ~0.3 ms radiative lifetime, EPR hyperfine structure, and paramagnetic response.

Conclusions:

• Doping with Mn2+ induces substantial, order-of-magnitude larger structural changes in (BA)2PbBr4 single crystals than typically observed.
• The observed structural distortion is thermodynamically favorable, providing insights into dopant-host interactions.
• These findings support the rational design of dilute magnetic semiconductors for advanced spin-based information technologies.