High Throughput Screening for Spin-Polarized Current in Noncollinear Magnetic Materials | NHR-Verein: Wir sind Hochleistungsrechnen

The spin-dependent transport phenomena in magnetic materials can provide spin-polarized charge current and large pure spin current, which could be achieved premised on two fundamental properties, i.e., anomalous Hall conductivity (AHC) and spin Hall conductivity [1]. The AHC is characterized as a generation of transverse voltage drop or current density (depending on the boundary conditions) originating from the longitudinal electric currents. The existence of ﬁnite AHC in noncollinear antiferromagnets has attracted noticeable attention due to possible applications in antiferromagnetic spintronics for information storage and data processing [2], where the kagome lattice turns out to be an intriguing prototypical lattice to host giant AHC with noncollinear magnetic configuration [3]. In this work, we proposed and studied antiperovskites (APVs) as a new class of magnetic materials exhibiting significant AHC in frustrated antiferromagnetic states [4].

Body:

Method

DFT calculations are performed using the projector augmented wave method as effectuated in the VASP package [5]. The AHC is evaluated using the WannierTools code [6], with the maximally localized Wannier functions (MLWFs) [7] constructed automatically based on an in-house developed algorithm [8].

Results:

In this work, we carried out a systematic analysis of 54 cubic APV systems (space group Pm3m) with the chemical formula M3XZ to determine their magnetic ground states and transport properties [8]. As shown in Fig. 1, Γ_4g and Γ_5g are the two most common noncollinear magnetic conﬁgurations reported for APVs, with the 120° magnetic angle conﬁgurations lying in the (111)-plane. The Γ_4g state can be obtained from Γ_5g by simultaneously rotating the moments of three M-atoms within the (111)-plane by 90°. Explicit calculations were performed to obtain the energies of eight possible magnetic configurations, with four of them shown in Fig. 1, i.e., Γ_4g, Γ_5g, non-magnetic (NM), ferromagnetic (FM). It is observed that fourteen APVs end up with noncollinear ground state, including newly-predicted Cr₃XN (X = Ir and Pt) with the Γ_4g magnetic ground state. Large AHC is observed for the APVs with the Γ_4g ground state, such as the AHC of Cr₃IrN and Cr₃PtN are 414.6 and 278.6 S/cm, respectively. More interestingly, detailed analysis reveals that AHC and the concomitant anomalous Nernst conductivity (ANC) can get significantly enhanced when topologically protected Weyl nodes are shifted towards the Fermi energy, which can be achieved by applying epitaxial strain as demonstrated for Mn₃PdN. Nevertheless, we found that such Weyl nodes are not something unique only for those systems with a noncollinear magnetic ground state, but also for all the magnetic materials with ferromagnetic ground states [10, 11].

Ongoing work

This work is published in the npj Computational Materials journal [9].

References

1. Nagaosa, N., et al. Anomalous Hall effect. Rev. Mod. Phys. 82, 1539–1592 (2010).

2. Liu, E. et al. Giant anomalous Hall effect in a ferromagnetic kagome-lattice semimetal. Nat. Phys. 14, 1125–1131 (2018).

3. Chen, H., et al. Anomalous Hall effect arising from non-collinear antiferromagnetism. Phys. Rev. Lett. 112, 017205–017209 (2014).

4. Samathrakis, I., et al. Tailoring the anomalous Hall effect in the noncollinear antiperovskite Mn3GaN. Phys. Rev. B 101, 214423–214428 (2020).

5. Kresse, G., et al. J. Efﬁcient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).

6. Wu, Q., et al. Wanniertools: an open-source software package for novel topological materials. Comput. Phys. Commun. 224, 405–416 (2018).

7. Mostoﬁ, A.A. et al. wannier90: a tool for obtaining maximally-localised wannier functions. Comput. Phys. Commun. 178, 685–699 (2008).

8. Zhang, Z., et al. High-throughput screening and automated processing toward novel topological insulators. J. Phys. Chem. Lett. 9, 6224-6231 (2018)

9. Singh, H.K., et al. Multifunctional antiperovskites driven by strong magnetostructural coupling. npj Comput Mater 7, 98 (2021).

10. Singh, H.K., et al., Giant anomalous Hall and anomalous Nernst conductivities in antiperovskites and their tunability via magnetic fields, arXiv:2107.13496

11. Samathrakis, I., et al. Enhanced anomalous Nernst effects in ferromagnetic materials driven by Weyl nodes, J. Phys. D: Appl. Phys. 55, 074003 (2021).