Strain induced disordered phonon modes in Cr doped PrFeO₃

Area of Science:

• Materials Science
• Condensed Matter Physics
• Spectroscopy

Background:

• Understanding the interplay between structural disorder and electronic/phononic properties is crucial for materials development.
• Polycrystalline PrFeO3 doped with Chromium (Cr) offers a tunable system to investigate these effects.

Purpose of the Study:

• To investigate the impact of Cr doping on structural disorder in PrFeO3.
• To correlate structural disorder with changes in electronic and phononic states using spectroscopy.

Main Methods:

• Room temperature optical absorption spectroscopy (OAS) and Raman spectroscopy were employed.
• Polycrystalline Cr-doped PrFeO3 samples were synthesized via a wet chemical route.
• X-ray diffraction (XRD) analysis was performed to assess structural properties.

Main Results:

• OAS revealed a systematic increase in electronic disorder with Cr doping.
• Raman spectroscopy showed shifting line shapes and broadening, attributed to doping-induced structural disorder and crystallographic strain.
• A new disorder phonon mode at ~510 cm⁻¹ was observed, linked to strain-induced disorder.
• A strong correlation was found between crystallographic strain, Raman line width, disorder parameter (σ), and Urbach energy.

Conclusions:

• Structural disorder significantly influences both electronic and phononic states in Cr-doped PrFeO3.
• The study establishes a link between crystallographic strain, electronic disorder (Urbach energy), and phonon behavior (Raman line width).
• This research provides insights into the relationship between tail states, structural disorder, and anharmonic effects in materials.