Computational design of double transition metal MXenes with intrinsic magnetic properties.

Two-dimensional transition metal carbides (MXenes) have great potential to achieve intrinsic magnetism due to their available chemical and structural diversity. In this work, by spin-polarized density functional theory calculations, we designed and comprehensively investigated 50 double transition metal (DTM) MXenes MCr 2 CT x (T = H, O, F, OH, or bare) based on the chemical formula of M 2 C (M = Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W). We highlight that ferromagnetic half-metallicity, antiferromagnetic semiconduction, as well as antiferromagnetic half-metallicity have been achieved in the DTM MXenes. Herein, ferromagnetic half-metallic ScCr 2 C 2 , ScCr 2 C 2 H 2 , ScCr 2 C 2 F 2 , and YCr 2 C 2 H 2 are characterized with wide band gaps and high Curie temperatures. Very interestingly, the ScCr 2 C 2 -based magnetic tunnel junction presents a tunnel magnetoresistance ratio as high as 176 000%. In addition, the antiferromagnetic semiconducting TiCr 2 C 2 , ZrCr 2 C 2 , and ZrCr 2 C 2 (OH) 2 , possessing moderate band gaps and high Néel temperatures, have been predicted. Especially, the Néel temperature of ZrCr 2 C 2 (OH) 2 can reach 425 K. Moreover, the Dirac cone-like band structure feature is highlighted in antiferromagnetic half-metallic ZrCr 2 C 2 H 2 . Our study provides a new potential strategy for designing MXenes in spintronics.