Hypothetical P63/mmc-Type CsCrCl3 Ferromagnet: Half-Metallic Property and Nodal Surface State

Yang Li

doi:10.3389/fmats.2020.00262

Abstract

This work is focusing on the electronic, magnetic, half-metallic behaviors, and interesting surface state of hypothetical CsCrCl3 ferromagnet with P63/mmc space group that are investigated under the spin-polarized Generalized Gradient Approach (GGA) and spin-polarized GGA plus Hubbard U correction within the framework of the Density Functional Theory (DFT). The calculated total magnetic moment of P63/mmc CsCrCl3 is ~7.397 µB, and the mainly contribution to the total magnetism is coming from the Cr atoms. Based on obtained spin-polarized band structures, we confirmed that this hypothetical CsCrCl3 is a half-metal with 100% spin-polarization. Without spin-orbit coupling, i.e., the spin and the orbit degrees of freedom are dependents, we found that there should be a interesting nodal surface state at kz = plane due to P63/mmc type lattice structure enjoys a two-fold screw axis S2z. Our study can be seen as a strong evidence to exhibit that the protected nodal surface state can be achieved in magnetic materials.

Highlights

The search for half-metallic materials (De Groot et al, 1983; Pickett and Moodera, 2001; Elfimov et al, 2002; Kusakabe et al, 2004; Zhang et al, 2018) with 100% spin-polarization (P) (Žutic et al., 2004) is a hot research topic in next-generation spintronics (Li and Yang, 2016)
We predict that the CsCrCl3 ferromagnet is an excellent half-metal with a large band gap and a half-metallic gap. This CsCrCl3 ferromagnet has a nodal surface state in the spin-up channel when the spin-orbit coupling (SOC) effect is not taken into consideration
The nodal surface state in the spin-up channel is due to the P63/mmc lattice structure, which features a twofold screw axis S2z

Summary

Introduction

The search for half-metallic materials (De Groot et al, 1983; Pickett and Moodera, 2001; Elfimov et al, 2002; Kusakabe et al, 2004; Zhang et al, 2018) with 100% spin-polarization (P) (Žutic et al., 2004) is a hot research topic in next-generation spintronics (Li and Yang, 2016). We use density functional theory (DFT) calculations to systematically investigate the electronic, magnetic, and half-metallic properties of the hypothetical CsCrCl3 ferromagnet, as well as a topological nodal surface signature, with respect to its potential applications in next-generation spintronics and electronics devices. We predict that the hypothetical CsCrCl3 ferromagnet is a novel material cofeaturing a half-metallic property and nodal surface state at the kz = π plane.

Results

Conclusion