Pressure-driven structural phase transitions and metallization in the two-dimensional ferromagnetic semiconductor...

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Two-dimensional (2D) magnetic materials are crucial for next-generation electronic and spintronic devices.
• Understanding the behavior of these materials under external stimuli like pressure is essential for their practical application.

Purpose of the Study:

• To investigate the high-pressure structural, magnetic, and electrical transport properties of chromium tribromide (CrBr3).
• To explore the effects of hydrostatic and non-hydrostatic conditions on the phase transitions and electronic behavior of CrBr3.
• To elucidate the reversibility and pressure hysteresis of these transitions.

Main Methods:

• High-pressure experiments utilizing Raman scattering and electrical conductivity measurements.
• Advanced characterization using high-resolution transmission electron microscopy (HRTEM).
• Theoretical validation through first-principles calculations.

Main Results:

• CrBr3 exhibits a second-order structural transition at 9.5 GPa.
• Under non-hydrostatic conditions, semiconductor-to-metal and magnetic switching occurs at 25.9 GPa.
• Significant pressure hysteresis (∼3.0 GPa) and sluggishness (∼5.0 GPa) were observed during compression and decompression, influenced by deviatoric stress.

Conclusions:

• The study reveals the complex pressure-induced phase transitions in CrBr3, highlighting the role of hydrostatic conditions.
• The observed reversibility and hysteresis provide critical insights into the material's response to pressure.
• Findings advance the understanding of 2D magnetic materials and their potential in spintronic and electronic devices.