Two-Dimensional Organic-Inorganic Room-Temperature Multiferroic

TL;DR

This paper uses first-principle calculations to uncover a magnetic coupling mechanism in 2D organic-inorganic multiferroics and demonstrates the design of a room-temperature multiferroic material.

Contribution

It reveals the origin of magnetic coupling in 2D organic-inorganic systems and proposes a rational design approach for room-temperature multiferroics.

Findings

Identified a molecular orbital-mediated magnetic coupling mechanism.

Designed a 2D room-temperature multiferroic material, Cr(h-fpyz)2.

Showed ferroelectricity can be introduced without altering the molecular valence state.

Abstract

Organic-inorganic multiferroics are promising for the next generation of electronic devices. To date, dozens of organic-inorganic multiferroics have been reported; however, most of them show magnetic Curie temperature much lower than room temperature, which drastically hampers their application. Here, by performing first-principle calculations and building effective model Hamiltonians, we reveal a molecular orbital-mediated magnetic coupling mechanism in two-dimensional Cr(pyz)2 (pyz=pyrazine), and the role that the valence state of the molecule plays in determining the magnetic coupling type between metal ions. Based on these, we demonstrate that a two-dimensional organic-inorganic room-temperature multiferroic, Cr(h-fpyz)2 (h-fpyz= half-fluoropyrazine), can be rationally designed by introducing ferroelectricity in Cr(pyz)2 while keeping the valence state of the molecule unchanged. Our work not only reveals the origin of magnetic coupling in 2D organic-inorganic systems, but also provides a way to design room temperature multiferroic materials rationally.