Five AFM spin configurations (a)–(e) of a ZB Mn8Te8 system in a 1 × 1 × 2 supercell. The purple balls represent Mn ions, with up and down arrows indicating spin orientation.
Nonequivalent substitutional cation sites with TM pairs distributed in the nearest neighbors (configurations O-1, O-2, and O-3) and next nearest neighbors (configurations O-A, O-B, and O-C) in the ZB MnTe host.
(a) Partial density of states of Ni 3d electrons in ZnTe and MnTe hosts, with t2g and e2g levels represented by red solid and green dashed lines, respectively. (b) Configurations of TM 3d electrons in tetrahedral hosts. The up and down arrows represent spin-polarized d electron occupations while the circles represent unoccupied TM d band levels.
GGA + U calculated (a) total densities of states of MnTe:Fe, (b) partial densities of states of MnTe:Fe, (c) partial densities of states of ZnTe:Fe for the next NN configuration.
(a) Clustering energies of TM impurities in nonmagnetic ZnTe and CdTe hosts (highlighted in blue), as well as for lattices artificially varied by ±2%. The open and solid squares represent the clustering energies of a and a configurations, respectively, with respect to the NN configuration. Clustering energies of TM impurities in MnTe are also shown for comparison. (b) Comparison of clustering energies and TM distance for the NN configuration for various TMs in the ZnTe host (similar correlation is found for CdTe and MnTe hosts). Red triangles represent the distance of TM pairs in NN.
Total and decomposed clustering energies (with respect to the NN configuration) of MnTe:TM systems, with configuration indicated by separation distance. Red line segments represent total clustering energies, while black and green shadow bars represent the size and Mn background effects, respectively. Positive values indicate clustering tendency, while negative values indicate a trend towards relatively uniform distribution. The corresponding GGA + U results for MnTe:Fe are shown in the inserted plot.
Magnetic exchange energies, EEX = EAFM − EFM , of TM pairs in ZnTe and CdTe hosts (highlighted in blue), as well for lattices artificially varied by ±2%. Open diamonds represent the a /2 configuration, while the open and solid squares represent the a and a configurations, respectively. EEX of TM pairs in MnTe are also illustrated for comparison.
Total and decomposed exchange energies of MnTe:TM systems, with pair configurations indicated by separation distance. Red line segments represent total exchange energies, while black and green shadow bars represent the size and Mn background effects, respectively. Positive and negative exchange energies correspond to favoring of FM and AFM coupling, respectively. The corresponding GGA + U results for MnTe:Fe are shown in the inserted plot.
Comparison of five AFM spin configurations of Mn8Te8. E0 is the total energy of each configuration with respect to that of AFM-III configuration. a0 is the optimized crystal constant. d Mn−Te is the distance between the TM impurity and its four nearest anions, Te. The energies in brackets are calculated with GGA + U method at fixed tetrahedral lattice of a = 6.34 Å, c/a = 1.
Total energy differences of MnTe:TM systems with TM pair configurations at a separation of d pair = a, and the nonequivalent configurations of d pair = a/2 and d pair = a. For each dopant pair, the total energy is relative to the most stable configuration, which is set to zero. The GGA + U calculation for O-A of case a for MnTe:Fe is hard to be converged, and thus denoted with a dash.
Article metrics loading...
Full text loading...