Spatial distribution of substitutional Mn-As clusters in ferromagnetic (Zn,Sn,Mn)As2 thin films revealed by image reconstruction of atom probe tomography data

Abstract

The ferromagnetic transition in (Zn,Sn,Mn)As2 thin films is explained in terms of magnetic percolation in a Mn-As clustering network. We first studied the relationship between the spatial distribution of Mn-As clusters and the Curie temperature (TC). The local atomic structure was reconstructed from datasets of atomic positions in (Zn,Sn,Mn)As2 obtained by atom probe tomography (APT). To probe the local atomic structure and the magnetic properties of Mn-As clusters in ZnSnAs2 thin films, we investigated molecular beam epitaxially grown (Zn,Sn,Mn)As2 samples doped with 2.1 and 3.6 at. % Mn. Representative regions with a low and high Mn concentration were extracted from APT datasets. Mn-As clusters containing 2-36 Mn atoms were identified in regions of high Mn concentration. We also obtained a correlation between TC and Mn-As clustering that was consistent with not only the experimental results but also first-principles calculations using the mean-field approximation.

Epitaxial growth and characterization of Cr-doped ZnSnAs2thin films on InP substrates

“…This result may be related to the formation of condensed magnetic semiconductors, i.e. large clusters consisting of zinc-blende type Mn-As networks exhibiting halfmetallic ferromagnetism, which occurs at a Curie temperature (T C ) of more than 300 K. [20][21][22] While II-IV-V 2 thin films doped with Mn have been wellstudied so far, II-IV-V 2 thin films doped with Cr are also very interesting and, as a matter of fact, have been proposed as another promising candidate for realizing ferromagnetic semiconductors based on several theoretical predictions. [23][24][25] Earlier ventures concerning Cr-doped semiconductors have been mainly focused on II-VI semiconductor hosts such as CdSe, 26) CdTe 27) and ZnTe.…”