Unconventional distortion induced two-dimensional multiferroicity in a CrO₃ monolayer

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Two-dimensional (2D) multiferroic materials are crucial for high-density data storage due to their coexisting electric and spin polarization.
• The scarcity of intrinsic 2D multiferroic semiconductors with high thermal stability presents a significant challenge.

Purpose of the Study:

• To propose and investigate a novel mechanism for single-phase multiferroicity in 2D materials.
• To explore the potential of the CrO3 monolayer as a stable, single-phase multiferroic semiconductor.

Main Methods:

• First-principles calculations were employed to investigate the electronic and magnetic properties of the CrO3 monolayer.
• Analysis of crystal field effects on Cr-d orbitals to understand polarization mechanisms.

Main Results:

• The CrO3 monolayer exhibits single-phase multiferroicity, driven by unconventional distortion of the square antiprismatic crystal field.
• An in-plane electric polarization was induced, confirming its multiferroic semiconductor nature.
• A high magnetic Curie temperature (∼220 K) was predicted, surpassing many existing 2D multiferroic semiconductors.
• Both ferroelectric and antiferroelectric phases were observed, enabling electrical control of magnetism.

Conclusions:

• The CrO3 monolayer represents a promising candidate for advanced 2D multiferroic applications.
• The findings offer insights into the magnetic and electric behavior of 2D multiferroics.
• This research encourages further exploration of 2D electromagnetics and spintronics for data storage and energy applications.