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arXiv · 2003.13327

Impact of Next-Nearest-Neighbor hopping on Ferromagnetism in Diluted Magnetic Semiconductors

Sourav Chakraborty·Subrat K Das·Kalpataru Pradhan
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Abstract

Being a wide band gap system GaMnN attracted considerable interest after the discovery of highest reported ferromagnetic transition temperature $T_C$ $\sim$ 940 K among all diluted magnetic semiconductors. Later it become a debate due to the observation of either a ferromagnetic state with very low $T_C$ $\sim$ 8 K or sometimes no ferromagnetic state at all. We address these issues by calculating the ferromagnetic window, $T_C$ Vs $p$, within a $t-t'$ Kondo lattice model using a spin-fermion Monte-Carlo method on a simple cubic lattice. We exploit the next-nearest-neighbor hopping $t'$ to tune the degree of delocalization of the free carriers and show that carrier localization (delocalization) significantly widen (shrunken) the ferromagnetic window with a reduction (enhancement) of the optimum $T_C$. We connect our results with the experimental findings and try to understand the ambiguities in ferromagnetism in GaMnN.

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Sourav Chakraborty, Subrat K Das, Kalpataru Pradhan. 2020-12-15. Impact of Next-Nearest-Neighbor hopping on Ferromagnetism in Diluted Magnetic Semiconductors. https://doi.org/10.1103/physrevb.102.245112

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