Toward Tunable Magnetic Dirac Semimetals: Mn Doping of Cd$_3$As$_2$

TL;DR

This paper demonstrates the successful incorporation of manganese into Cd3As2 Dirac semimetal thin films via molecular beam epitaxy, showing potential for inducing tunable magnetic topological phases with high electron mobility.

Contribution

It presents a method to dope Cd3As2 with Mn while maintaining high mobility, and provides initial evidence of electronic structure changes indicating a Weyl phase.

Findings

Mn doping achieved >10% in Cd3As2 thin films

High electron mobilities (>10,000 cm²/Vs) maintained up to 5% Mn

Preliminary evidence of Mn-induced Weyl phase transition

Abstract

Magnetic impurities provide a route toward increasing functionality in electronic materials, often enabling new device concepts and architectures. In the case of topological semimetals, dilute magnetic doping presents a particularly attractive approach for inducing a Dirac to Weyl phase change via time reversal symmetry breaking. However, efforts to realize changes in the electronic structure have been limited by challenges in incorporating magnetic impurities into crystals with sufficiently high electron mobilities to detect them via transport or spectroscopic techniques. Here, we demonstrate incorporation of Mn into Cd$_3$As$_2$ Dirac semimetal thin films grown by molecular beam epitaxy (MBE). Using As-rich growth conditions and [001] oriented thin films, Mn compositions of >10% are achieved. Films contain uniform distributions of Mn with no evidence of secondary phases and exhibit electron mobilities greater than 10,000-30,000 cm$^2$/Vs up to 5% Mn. An evolution in the magnetization behavior along with the emergence of a second quantum oscillation frequency at low Mn concentrations provide preliminary evidence of Mn-induced changes in the electronic structure that are consistent with a Weyl phase. This work demonstrates the potential of magnetically doping topological semimetal thin films and a pathway for synthesizing them.