<i>Ab-initio</i>study of exchange constants and electronic structure in diluted magnetic group-IV semiconductors

Picozzi, Silvia

doi:10.1088/1367-2630/10/5/055017

Cited by 9 publications

(6 citation statements)

References 28 publications

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“…The attribution of the Mn 2þ electronic configuration to the ternary Therefore, the allowed compounds have a half-metallic ferromagnetic behavior. A similar result was obtained by Silvia Picozzi and Marjana Lezaic in a first principles study on diluted magnetic group-IV semiconductors [26].…”

Section: Electronic Propertiessupporting

confidence: 84%

Half-metallic ferromagnetism of ZnxMn1−xO compounds: A first-principles study

Vargas‐Hernández

Cruz

2015

Computational Condensed Matter

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a b s t r a c tFirst-principle calculations were performed to investigate the structural, electronic and magnetic properties of Zn x Mn 1Àx O compounds (x ¼ 0.0, 0.25, 0.50, 0.75 and 1.0) in a wurtzite-type structure. The full-potential linearized augmented-plane-wave (FP-LAPW) method was used, as implemented in the WIEN2k code. The analysis of the structural properties shows that the constant increases linearly according to Vegard's law, with the increment of the Zn concentration in the structure, while the bulk modulus increases. The electronic density studies show that the Zn x Mn 1Àx O compounds (x ¼ 0.25, 0.50 and 0.75) have a half-metallic behavior with a magnetic spin polarization of 100% and a magnetic moment of~5 m b /atom-Mn. The ferromagnetic state comes from the hybridization of the Mn-3d and O2p states that cross the Fermi level. These compounds are good candidates for spintronic applications.

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Section: Electronic Propertiessupporting

confidence: 84%

Half-metallic ferromagnetism of ZnxMn1−xO compounds: A first-principles study

Vargas‐Hernández

Cruz

2015

Computational Condensed Matter

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“…The ab initio electronic structure calculations within density functional theory show that such doping behaviors could result in relatively higher carrier hole concentrations and increased magnetic moments [27,58]. Complementary theoretical work using the frozen-magnon scheme also shows that the ferromagnetism is produced only through holes and Mn is a good source for generating holes in Ge system [62].…”

Section: Theories Of Ferromagnetism In Group IV Dmsmentioning

confidence: 95%

Magnetic Mn-Doped Ge Nanostructures

Xiu

2012

ISRN Condensed Matter Physics

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With the seemly limit of scaling on CMOS microelectronics fast approaching, spintronics has received enormous attention as it promises next-generation nanometric magnetoelectronic devices; particularly, the electric field control of ferromagnetic transition in dilute magnetic semiconductor (DMS) systems offers the magnetoelectronic devices a potential for low power consumption and low variability. Special attention has been given to technologically important group IV semiconductor based DMSs, with a prominent position for Mn doped Ge. In this paper, we will first review the current theoretical understanding on the ferromagnetism in MnxGe1−x DMS, pointing out the possible physics models underlying the complicated ferromagnetic behavior of MnxGe1−x. Then we carry out detailed analysis of MnxGe1−x thin films and nanostructures grown by molecular beam epitaxy. We show that with zero and one dimension quantum structures, superior magnetic properties of MnxGe1−x compared with bulk films can be obtained. More importantly, with MnxGe1−x nanostructures, such as quantum dots, we demonstrate a field controlled ferromagnetism up to 100 K. Finally we provide a prospective of the future development of ferromagnetic field effect transistors and magnetic tunneling junctions/memories using dilute and metallic MnxGe1−x dots, respectively. We also point out the bottleneck problems in these fields and rendering possible solutions to realize practical spintronic devices.

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“…The supercell ab initio approach 53,54,55,56,57 employed here assumes only one approximation, the pairsuperposition approximation, which means that the interaction is exclusively pairwise and can be added independently to get the total interaction. Though this may not hold at high concentrations of magnetic moments, we claim that it should be a reasonable approximation at the low concentrations we considered (3.13%-6%), where the average distance between two Mn atoms, calculated by d = 2 with x the concentration and a the lattice constant, ranges from 1.97a to 1.58a, or 11.39 Å to 9.14 Å in the case of Mn doped Ge.…”

Section: Curie Temperaturementioning

confidence: 99%

Optimization of Mn doping in group-IV-based dilute magnetic semiconductors by electronic codopants

et al. 2009

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The percentage of substitutional doping of magnetic atoms (Mn) in group-IV-based dilute magnetic semiconductors (DMS) can be increased by co-doping with another conventional electronic dopant (e-dopant), as demonstrated from first-principles calculations recently [Zhu et al., Phys. Rev. Lett. 100, 027205 (2008)]. Here, we report extensive theoretical investigations of the kinetic and thermodynamic characteristics of several co-doped systems including bulk Si and Ge as hosts and various group-III and group-V e-dopants. The main findings are as follows: The n-p pairing of n-type e-dopants with p-type substitutional Mn is energetically stable in bulk Ge and Si. Mn atoms move from interstitial sites to substitutional sites easier (with lower kinetic barriers) in the presence of a neighboring n-type e-dopant. Magnetic coupling between two Mn atoms in bulk Ge oscillates between positive (ferromagnetic) and negative (antiferromagnetic) values with increasing Mn-Mn distance, but in Mn/As co-doped Ge the coupling parameter remains positive at all distances beyond nearest-neighbors and this qualitative difference does not change with the doping level. For Mn doped Si, all coupling values except for the nearest neighbor one are positive and do not change much upon co-doping. We find an unconventional magnetic anisotropy in the co-doped system, that is, the dependence of magnetic coupling on the relative positions of the magnetic ions and their neighboring e-dopants. We map the calculated magnetic coupling to a classical Heisenberg model and employ Monte Carlo simulations to estimate the Curie temperature (Tc). We find that in Mn doped Ge no ferromagnetic order exists for Mn concentrations ranging from 3.13% to 6%. Instead, a spin-glass phase transition occurs at ∼5 K at 5% Mn doping. For Mn/As co-doped Ge, Tc increases nearly linearly with the Mn concentration and reaches 264 K at 5% Mn doping.

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Ab-initiostudy of exchange constants and electronic structure in diluted magnetic group-IV semiconductors

Cited by 9 publications

References 28 publications

Half-metallic ferromagnetism of ZnxMn1−xO compounds: A first-principles study

Half-metallic ferromagnetism of ZnxMn1−xO compounds: A first-principles study

Magnetic Mn-Doped Ge Nanostructures

Optimization of Mn doping in group-IV-based dilute magnetic semiconductors by electronic codopants

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