Magnetic structure of EuZn${}_2$Sb${}_2$ single-crystal thin-film

Abstract

Magnetic topological materials are a class of compounds which can host massless electrons controlled by the magnetic order. One such compound is EuZn${}_2$Sb${}_2$, which has recently garnered interest due to its strong interplay between the Eu magnetism and charge carriers. However the topology of the electronic band structure, which depends on the ground state magnetic configuration of the europium sublattice, has not been determined. Based on our \textit{ab-initio} calculations, we find that an in-plane and out-of-plane \textit{A}-type antiferromagnetic (AFM) order generates a topological crystalline insulator and Dirac semimetal respectively, whereas a ferromagnetic (FM) order stabilizes a Weyl semimetal. Our resonant x-ray elastic scattering measurements of single-crystal thin film EuZn${}_2$Sb${}_2$ reveal both a sharp magnetic peak at $\text{Q}$=$(0,0,\frac{1}{2})$ and broad $\text{Q}$=$(0,0,1)$ below $T_{\mathrm{N}}=12.9$\,K, which is associated with an \textit{A}-type AFM and FM order, respectively. Our measurements indicate that the FM and AFM layers are spatially separated along the crystal $c$ axis, with the former limited to the top three atomic layers. We propose that EuZn${}_2$Sb${}_2$ behaves as a Weyl semimetal in the surface FM layers, and as a topological crystalline insulator in the lower AFM layers.

Accepted in PRB

References in corpus (14)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Progress and prospects in magnetic topological materials
• Resonant Elastic Soft X-Ray Scattering
• Properties of single crystalline AZn2Sb2 (A=Ca,Eu,Yb)
• Magnetic mixed valent semimetal EuZnSb${}_2$ with Dirac states in the band structure
• Intrinsic Magnetic Topological Materials
• A-type antiferromagnetic order and magnetic phase diagram of the trigonal Eu spin-7/2 triangular-lattice compound EuSn2As2
• Large unconventional anomalous Hall effect arising from spin chirality within domain walls of an antiferromagnet EuZn${}_2$Sb${}_2$
• Superexchange Interaction in Insulating EuZn${}_2$P${}_2$
• Maximizing intrinsic anomalous Hall effect by controlling the Fermi level in simple Weyl semimetal films
• Antiferromagnetic topological insulator with selectively gapped Dirac cones
• Intrinsic insulating transport characteristics in low-carrier density EuCd2As2 films
• Stark difference in the in-plane anomalous Hall response in Zintl compounds EuA2Sb2 (A = Zn, Cd) thin films
• Observation of paramagnetic spin-degeneracy lifting in EuZn2Sb2