Screening magnetic two-dimensional atomic crystals with nontrivial electronic topology

TL;DR

This study uses high-throughput first-principles calculations to identify 89 2D magnetic monolayers with promising magnetic and electronic properties, including high Curie temperatures and exotic quantum states, aiding future spintronics research.

Contribution

It provides a comprehensive database of 2D magnetic materials with novel electronic phases, including high-TC candidates and new fermion types, advancing material discovery for spintronics.

Findings

89 magnetic monolayers identified, including 56 ferromagnetic and 33 antiferromagnetic.

24 ferromagnetic monolayers with Curie temperatures higher than CrI3.

Discovery of a new type-II Weyl ring fermion in ScCl.

Abstract

To date only a few two-dimensional (2D) magnetic crystals were experimentally confirmed, such as CrI3 and CrGeTe3, all with very low Curie temperatures (TC). High-throughput first-principles screening over a large set of materials yields 89 magnetic monolayers including 56 ferromagnetic (FM) and 33 antiferromagnetic compounds. Among them, 24 FM monolayers are promising candidates possessing TC higher than that of CrI3. High TC monolayers with fascinating electronic phases are identified: (i) quantum anomalous and valley Hall effects coexist in a single material RuCl3 or VCl3, leading to a valley-polarized quantum anomalous Hall state; (ii) TiBr3, Co2NiO6 and V2H3O5 are revealed to be half-metals. More importantly, a new type of fermion dubbed type-II Weyl ring is discovered in ScCl. Our work provides a database of 2D magnetic materials, which could guide experimental realization of high-temperature magnetic monolayers with exotic electronic states for future spintronics and quantum computing applications.