Half-metallic ferromagnetism in substitutionally doped boronitrene

Ukpong, Aniekan Magnus; Chetty, Nithaya

doi:10.1103/physrevb.86.195409

Cited by 11 publications

(10 citation statements)

References 76 publications

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“…Some examples of such collective phenomena include formation of Hofstadter's butterfly in graphene/boron nitride (hBN) heterostructures, giant tunneling magnetoresistance in ferromagnet/ vdW multilayers and interlayer coupling of electron-phonon modes in vdW heterostructures [5]. Consider that first principles calculations of the ground state properties of free-standing hBN monolayers show that decoration of the nitrogen vacancyantisite complex with charges [6], and functionalization of the hBN monolayer with substitutional carbon antisite complexes of boron and its surrounding nitrogen atoms (C 1B + C 3N ) [7], induce temperature independent magn etic moments. Though this defect-induced magnetic moment in hBN is not strictly a ferromagnetic state [8], it is shown herein that spin filtering in Fe-hBN/graphene magnetic tunnel junction (MTJ) devices can be used to offer an alternative pathway for quantum information encoding [9].…”

Section: Introductionmentioning

confidence: 99%

Ab initiostudies of coherent spin transport in Fe-hBN/graphene van der Waals multilayers

Ukpong¹

2017

J. Phys.: Condens. Matter

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This paper presents the results of ab initio studies of the electronic spin inversion and filtering in a ferromagnetic multilayer heterostructure. Spin-polarized electronic structure calculations are performed based on van der Waals density functional theory to give unique insights in to the generation, manipulation and transport of coherent spin conductance. By using an exact theory of the self-consistent ground state of the Fe-hBN/graphene multilayer as a model of the magnetic tunnel junction, hidden asymmetries are unraveled in the spin-resolved charge densities. It is shown that the injection of spin into the graphene/boron nitride tunnel layer from a ferromagnetic contact gives rise to coherent spin current. The projected Fermi surfaces of the up and down spin channels are analyzed to reveal Fermi arc topologies and spin anisotropies. It is also demonstrated that the coherent transport of pure spin-down current in the topological Weyl semimetal phase is robust. The implications of the results on out-of-plane transport of spin polarized conductance in van der Waals multilayer spintronic devices is discussed. The insights derived from this study are expected to open up prospects for further exploration of van der Waals magnetic multilayer heterostructures as a versatile platform for developing materials for Weyltronic applications.

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Section: Introductionmentioning

confidence: 99%

Ab initiostudies of coherent spin transport in Fe-hBN/graphene van der Waals multilayers

Ukpong¹

2017

J. Phys.: Condens. Matter

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“…[13][14][15][16][17][18][19][20][21] These special features make the nonmetal doped h-BN system a potential candidate for spin-based device exploitation (which utilizes the electronic spin states for data storage and processing). The search for suitable Half-MetallicFerromagnet (HMFM) materials started in 1983 after the De Groot et al [22] discovery.…”

Section: Introductionmentioning

confidence: 99%

“…[19,[38][39][40][41] It was reported that the C impurity spontaneously induces magnetization and half-metallic character. [19][20][21][38][39][40][41] Ukpong et al [21] have shown via DFT calculations that the induced magnetic moments are easily affected by the size of the embedded C impurity cluster and edge termination. Berseneva et al [20] reported that the C substitution processes are controlled by the energetics of the atomic configurations, more especially when the system is charged.…”

Section: Introductionmentioning

confidence: 99%

“…Recent characterizations of non-metal doped h-BN monolayer revealed interesting features such as magnetism and half-metallic character [13][14][15][16][17][18][19][20][21]. These special features make the non-metal doped h-BN system a potential candidate for spin-based device exploitation (which utilizes the electronic spin states for data storage and processing).…”

Section: Introductionmentioning

confidence: 99%

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Defect charge states in Si doped hexagonal boron-nitride monolayer

Mapasha

Molepo

Andrew

et al. 2016

J. Phys.: Condens. Matter

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We perform ab-initio density functional theory calculations to investigate the energetics, electronic and magnetic properties of isolated stoichiometric and non-stoichiometric substitutional Si complexes in a hexagonal boron-nitride monolayer. The Si impurity atoms substituting the boron atom sites Si B giving non-stoichiometric complexes are found to be the most energetically favourable, and are half-metallic and order ferromagnetically in the neutral charge state. We find that the magnetic moments and magnetization energies increase monotonically when Si defects form a cluster. Partial density of states and standard Mulliken population analysis indicate that the half-metallic character and magnetic moments mainly arise from the Si 3p impurity states. The stoichiometric Si complexes are energetically unfavorable and non-magnetic.When charging the energetically favourable non-stoichiometric Si complexes, we find that the formation energies strongly depend on the impurity charge states and Fermi level position. We also find that the magnetic moments and orderings are tunable by charge state modulation q = -2, -1, 0, +1, +2. The induced half-metallic character is lost (retained) when charging isolated (clustered) Si defect(s). This underlines the potential of a Si doped hexagonal boron-nitride monolayer for novel spin-based applications.

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“…We thus adopt the Heisenberg Hamiltonian

to interpret the field-induced band magnetism, where J is the magnetic exchange coupling. Here S i denotes the total spin magnetic moment at atomic site i obtained as the vector sum over all the spins of unpaired electrons, with i and j labeling two nearest-neighbor sites [ 63 ].…”

Section: Resultsmentioning

confidence: 99%

Quantum Phase Transition in the Spin Transport Properties of Ferromagnetic Metal-Insulator-Metal Hybrid Materials

Hussien

Ukpong

2022

Nanomaterials

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Perpendicular magnetic tunnel junctions provide a technologically important design platform for studying metal-insulator-metal heterostructure materials. Accurate characterization of the sensitivity of their electronic structure to proximity coupling effects based on first-principles calculations is key in the fundamental understanding of their emergent collective properties at macroscopic scales. Here, we use an effective field theory that combines ab initio calculations of the electronic structure within density functional theory with the plane waves calculation of the spin polarised conductance to gain insights into the proximity effect induced magnetoelectric couplings that arise in the transport of spin angular momentum when a monolayer tunnel barrier material is integrated into the magnetic tunnel junction. We find that the spin density of states exhibits a discontinuous change from half-metallic to the metallic character in the presence of monolayer hexagonal boron nitride when the applied electric field reaches a critical amplitude, and this signals a first order transition in the transport phase. This unravels an electric-field induced quantum phase transition in the presence of a monolayer hexagonal boron nitride tunnel barrier quite unlike molybdenum disulphide. The role of the applied electric field in the observed phase transition is understood in terms of the induced spin-flip transition and the charge transfer at the constituent interfaces. The results of this study show that the choice of the tunnel barrier layer material plays a nontrivial role in determining the magnetoelectric couplings during spin tunnelling under external field bias.

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Half-metallic ferromagnetism in substitutionally doped boronitrene

Cited by 11 publications

References 76 publications

Ab initiostudies of coherent spin transport in Fe-hBN/graphene van der Waals multilayers

Ab initiostudies of coherent spin transport in Fe-hBN/graphene van der Waals multilayers

Defect charge states in Si doped hexagonal boron-nitride monolayer

Quantum Phase Transition in the Spin Transport Properties of Ferromagnetic Metal-Insulator-Metal Hybrid Materials

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