Synthesis and characterization of Ge–Cr-based intermetallic compounds: GeCr3, GeCCr3, and GeNCr3

High-Throughput Screening of Magnetic Antiperovskites

“…For such alloys, larger deviations from the already-mentioned stability criteria are expected (when calculated as stoichiometric M 3 XZ compounds in the cubic Pm m structure). The reported noncubic APVs such as Cr 3 AsN, Cr 3 GeC, Cr 3 GeN, , and Mn 3 GeC , have a lower formation energy compared to the Pm m cubic structure in our HTE database and are found to be thermodynamically stable (see Table S2). In addition, from our calculations, we confirmed that the reported noncubic structures of Mn 3 GeN and Cr 3 AsC have lower formation energy than the cubic Pm m and are thermodynamically stable (see Table S2).…”

“…The imaginary mode throughout the BZ for Cr 3 AsN might be due to strong phonon coupling between the R 4 + and other phonon modes. For APVs in the Cmcm space group, only Cr 3 GeC has the M 3 + –R 4 + imaginary modes, while all other Cmcm APVs exhibit imaginary modes in the whole BZ. Taking Cr 3 GeC as an example, it is confirmed that there is no imaginary phonon mode in the phonon dispersions calculated using the Cmcm crystal structure, as shown in Figure .…”

“…For APVs in the Cmcm space group, only Cr 3 GeC has the M 3 + –R 4 + imaginary modes, while all other Cmcm APVs exhibit imaginary modes in the whole BZ. Taking Cr 3 GeC as an example, it is confirmed that there is no imaginary phonon mode in the phonon dispersions calculated using the Cmcm crystal structure, as shown in Figure . In this regard, for those compounds which are predicted to be thermodynamically stable on the basis of the formation energy and the distance to the convex hull but dynamically unstable (Table S5), they can probably be synthesized in crystal structures other than Pm m.…”

“…The space groups Cmcm and I 4/ mcm are subgroups of Pm m, originated from the imaginary mode of the R 4 + and M 3 + –R 4 + types, respectively. There are four APVs (Mn 3 GeC, Mn 3 GeN, , Fe 3 GeN, and Cr 3 AsN , ) with the I 4/ mcm structure and four (Cr 3 AsC, Cr 3 GeC, Cr 3 PN, , and Cr 3 PC , ) with the Cmcm space group. It is observed that the Mn 3 GeC and Mn 3 GeN display imaginary modes at the R point and that for Cr 3 AsN the imaginary modes extend in the whole BZ for the cubic Pm m structure.…”

Cr3GeN: A Nitride with Orthorhombic Antiperovskite Structure

“…Both structures can be derived from the cubic antiperovskite structure ( Pm 3̅ m ) by tilting of the Cr 6 C and Cr 6 N octahedra (see Figure ). Following this initial work in the 1970s, Lin et al synthesized Cr 3 Ge with the cubic perovskite structure as well as the tetragonal and orthorhombic antiperovskite nitride and carbide, Cr 3 GeN and Cr 3 GeC, respectively, to perform some more elaborate characterizations of their properties . Aside from their interesting properties, the crystal chemistry of this family of materials is also of immense interest due to multiple structural transitions.…”