Electronic structure and magnetic properties of Mn and Fe impurities near the GaAs (110) surface

Mahani, Mohammad Reza; Islam, M. F.; Pertsova, Anna; Canali, Carlo M.

doi:10.1103/physrevb.89.165408

Cited by 11 publications

(31 citation statements)

References 51 publications

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“…The hybridization is very weak for these e states compared to the previously observed t 2 states, which manifests in a much more localized apparent wave function for the e state than the simultaneously observed t 2 state around the same Fe impurity. A theoretical description of the electronic states requires a technique that can describe the wave function on tens of thousands of atoms while preserving the local orbital symmetry in the basis; this description can be implemented in a tight-binding theory that describes the electronic structure of the host using an empirical basis [26][27][28] and matches the 3d levels of the impurity from ab initio calculations, consistent with experimental measurements. With this approach, the theoretical calculations show excellent agreement with the spatial structure of the t 2 states and, with very weak 3d-4pπ hybridization between the Fe and the surrounding As atoms, provides excellent agreement for the spatial structure of the e states.…”

Section: Introductionmentioning

confidence: 99%

Observation of the symmetry of core states of a single Fe impurity in GaAs

Bocquel¹,

Kortan²,

Campion³

et al. 2017

Phys. Rev. B

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Bocquel, J.; Kortan, V.R.; Campion, R.P.; Gallagher, B.L.; Flatté, M.E.; Koenraad, P.M. Published in:Physical Review B DOI:10.1103/PhysRevB.96.075207Published: 23/08/2017 Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. We report the direct observation of two mid-gap core d states of differing symmetry for a single Fe atom embedded in GaAs. These states are distinguished by the strength of their hybridization with the surrounding host electronic structure. The midgap state of Fe that does not hybridize via σ bonding is strongly localized to the Fe atom, whereas the other, which does, is extended and comparable in size to other acceptor states. Tight-binding calculations of these midgap states agree with the spatial structure of the measured wave functions and illustrate that such measurements can determine the degree of hybridization via π bonding of impurity d states. These single-dopant midgap states with strong d character, which are intrinsically spin-orbit-entangled, provide an opportunity for probing and manipulating local magnetism and may be of use for high-speed electrical control of single spins.

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Section: Introductionmentioning

confidence: 99%

Observation of the symmetry of core states of a single Fe impurity in GaAs

Bocquel¹,

Kortan²,

Campion³

et al. 2017

Phys. Rev. B

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“…On the theoretical side, both first-principles calculations [12,13,14,15,16,17] and microscopic tightbinding (TB) models [18,19,20,21,22,23,24,25,26] have played an essential role in elucidating experimental findings and predicting new properties. Computationally efficient and physically motivated TB models have been particularly successful in describing electronic and magnetic properties of some TM impurities, such as Mn dopants with their associated acceptor states [18,19,21,22,23,24,26] and, more recently, Fe dopants [27] on the (110) GaAs surface. Due to their computational feasibility, microscopic TB models are especially well suited to study single impurities as they allow the use of large supercells, with sizes exceeding those accessible by first-principles approaches by several orders of magnitude.…”

Section: Introductionmentioning

confidence: 99%

“…Such models allow the calculation of measurable physical quantities, which can be directly probed in experiments (see Figure 1). In particular, finite-cluster TB calculations provide a detailed description of the in-gap electronic structure in the presence of the dopant close to the surface, which can be directly related to resonances in conductance spectra measured by STM [22,27]. Although a more elaborate treatment is required for simulations of STM topographic images, in the first approximation the tunneling current is proportional to the local density of states (LDOS) at the surface [28].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, TB calculations of the magnetic anisotropy landscape, combined with analysis of the shape and the spatial extent of the acceptor wavefunction, have been used to explain experimental results on magnetic-field manipulation of a single Mn acceptor near the (110) GaAs surface [26]. A similar strategy has been used to predict the effect of the magnetic field on the magnetic moment of Fe in GaAs and its dependence on the valence state of the dopant [27]. Here we report on recent advances in TB modeling of single substitutional Mn impurities, positioned near the (110) GaAs surface.…”

Section: Introductionmentioning

confidence: 99%

“…The finite-size effects, stemming from the limited size of the supercell in this type of calculations, have been identified and, to a great extent, controlled by systematically increasing the cluster size. Such detailed knowledge of the magnetic anisotropy energy, together with the calculated LDOS of the impurity-induced states in the gap, are crucial for a quantitative comparison with STM experiments, especially in the presence of external electric and magnetic fields [26,27]. The rest of the paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

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Trend of the magnetic anisotropy for individual Mn dopants near the (1 1 0) GaAs surface

Mahani¹,

Pertsova²,

Canali³

2014

J. Phys.: Condens. Matter

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Abstract. Using a microscopic finite-cluster tight-binding model, we investigate the trend of the magnetic anisotropy energy as a function of the cluster size for an individual Mn impurity positioned in the vicinity of the (110) GaAs surface, We present results of calculations for large cluster sizes, containing approximately 10 4 atoms, which have not been investigated so far. Our calculations demonstrate that the anisotropy energy of a Mn dopant in bulk GaAs found to be non-zero in previous tight-binding calculations, is purely a finite size effect and it vanishes as the inverse cluster size. In contrast to this, we find that the splitting of the three in-gap Mn acceptor energy levels converges to a finite value in the limit of infinite cluster size. For a Mn in bulk GaAs this feature is related to the nature of the mean-field treatment of the coupling between the impurity and its nearest neighbors atoms. Moreover, we calculate the trend of the anisotropy energy in the sublayers, as the Mn dopant is moved away from the surface towards the center of the cluster. Here the use of large cluster sizes allows us to position the impurity in deeper sublayers below the surface, compared to previous calculations. In particular, we show that the anisotropy energy increases up to the fifth sublayer and then decreases as the impurity is moved further away from the surface, approaching its bulk value. The present study provides important insight for experimental control and manipulation of the electronic and magnetic properties of individual Mn dopants at the semiconductor surface by means of advanced scanning tunneling microscopy techniques.

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Ab-initio studies on the electronic properties of Fe dopant in GaAs(1 1 0) surface

Fang

2016

Computational Materials Science

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Electronic structure and magnetic properties of Mn and Fe impurities near the GaAs (110) surface

Abstract: Combining density-functional theory calculations and microscopic tight-binding models, we investigate theoretically the electronic and magnetic properties of individual substitutional transitionmetal impurities (Mn and Fe) positioned in the vicinity of the (110)

Cited by 11 publications

References 51 publications

Observation of the symmetry of core states of a single Fe impurity in GaAs

Observation of the symmetry of core states of a single Fe impurity in GaAs

Trend of the magnetic anisotropy for individual Mn dopants near the (1 1 0) GaAs surface

Ab-initio studies on the electronic properties of Fe dopant in GaAs(1 1 0) surface

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