Electronic structures of III–V based ferromagnetic semiconductors: half-metallic phase

Park, J.H; Kwon, S. K.; Min, B. I.

doi:10.1016/s0921-4526(99)00984-9

Cited by 92 publications

(67 citation statements)

References 7 publications

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“…These results are consistent with the previous pSIC 20 and SIC 21 and the LDA+U [17][18][19] calculations. The e gshell in spin up (↑) is fully occupied, and the t 2g (↑) states are almost completely filled, with Löwdin's occupation analysis 38 giving range of values 2.74-2.85.…”

Section: Resultssupporting

confidence: 93%

Hole -character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches – Newly found spin-unpolarized gap states of s-type below 1 of Mn

Milowska

Wierzbowska

2014

Chemical Physics

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Hole sp 3 -character and delocalization in (Ga,Mn) The dilute magnetic semiconductor (Ga,Mn)As is ferromagnetic in accordance with the p-d Zener model. Hole density function (HDF) localization has been previously studied by means of the density functional theory (DFT) and non-standard DFT methods; however not for dopings near 1%. We have revised (Ga,Mn)As using the DFT with the pseudopotential self-interaction correction (pSIC) and maximally-localized Wannier functions (MLWFs), which show the sp 3 character of a HDF. Nature of HDF is extended -for low dopings and the pSIC, 70% of the HDF is located within the inter-impurities region, and contribution of the 3d-Mn states is 3-5% for 1-3% of Mn with the pSIC, and 11% with the DFT. We found that for dopings below 1%, the spin-unpolarized s-type impurity states segregate from the conduction band to the energy gap -in contrast to earlier publications. This implies that donor co-doped dilute samples would be both insulating and nonmagnetic.

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Section: Resultssupporting

confidence: 93%

Hole -character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches – Newly found spin-unpolarized gap states of s-type below 1 of Mn

Milowska

Wierzbowska

2014

Chemical Physics

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“…The frequency of this peak, ω * , depens on J and carrier density n. For intermediate coupling (J/W = 0.3 ÷ 0.4) and n = 0.02 we found 0.04 ≤ ω * /W ≤ 0.21. For Ga 1−x Mn x As the bandwidth 2W ≈ 4eV [5,16], yieding 0.1 eV ≤ ω * ≤ 0.4 eV, in reasonable agreement with the ones obtained by using Monte-Carlo simulation. This result is in semiqualitative agreement with the experiment results for Ga 1−x Mn x As for x = 0.052 where a broad peak is at around 0.2 eV [17,18].…”

Section: Numerical Results and Discussionsupporting

confidence: 88%

Optical properties of diluted magnetic semiconductors in coherent potential approximation

Hoang¹

2008

Physica B: Condensed Matter

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Abstract. We study optical properties of a single band model for (III,Mn)V diluted magnetic semiconductors (DMS), treating the impurity spins fully quantum mechanically in the coherent potential approximation (CPA). Our CPA results show an interesting dependence of the optical conductivity on Kondo coupling, carrier density, nonmagnetic potential, and temperature. We find that by taking into account the spin-flip effect the calculated conductivity is in resonable agreement with ones obtained by Monte-Carlo simulations and experiments.

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“…It has been conclusively established by the LDA calculations that in the presence of substitutional Mn, the Fermi energy crosses the valence band near the Γ point, introducing one hole per Mn. Clear theoretical evidence for As 4p-like band holes has been obtained in LDA+U calculations [20] and the Mn 3d density of states calculated by this method is in a good agreement with photoemission data [23]. As-antisite and Mn-interstitial defects act as a double donor, according to the microscopic calculations [19,21,22], and, therefore, are the likely sources of carrier compensation observed in experiment.…”

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confidence: 61%

Theoretical Models of Ferromagnetic III‐V Semiconductors

et al. 2003

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Recent materials research has advanced the maximum ferromagnetic transition temperature in semiconductors containing magnetic elements toward room temperature. Reaching this goal would make information technology applications of these materials likely. In this article we briefly review the status of work over the past five years which has attempted to achieve a theoretical understanding of these complex magnetic systems. The basic microscopic origins of ferromagnetism in the (III,Mn)V compounds that have the highest transition temperatures appear to be well understood, and efficient computation methods have been developed which are able to model their magnetic, transport, and optical properties. However many questions remain.It is hoped that the emerging field of semiconductor spintronics, which studies the controlled flow of charge and spin in a semiconductor, will lead to the development of new non-volatile, high-density, and high-speed information technologies. An important milestone in this field was the discovery five years ago of ferromagnetism in Mn-doped, p-type GaAs observed at temperatures in excess of 100 Kelvin [1]. Ferromagnetism at room temperature with full participation of itinerant carriers would be a major breakthrough in semiconductor spintronics. With this aim, intensive material research is currently in progress on transition metal doped III-V semiconductors. In this brief review we present a snap shot of the theoretical part of this endeavor, which has progressed hand in hand with experimental developments.A qualitative picture of the electronic structure of III-V diluted magnetic semiconductors (DMSs) was proposed by Dietl and coworkers [2,3]. Their model is based on the internal reference rule [6] which states that energy levels derived from the d-shell of the magnetic ion are constant across semiconductor compound families with properly aligned bands. The application of this rule to III-V materials is illustrated in Fig 1 for ionized magnetic impurities substituted on cation sites [2][3][4][5]. The position of the A 2 level for Mn in GaAs, deep in the valence band, suggests that Mn in GaAs is 2+, that its d-shell is occupied by five electrons, and that incorporation of Mn in this and many other (III,Mn)V compounds will result a large density of valence band holes that can mediate ferromagnetic coupling between the S = 5/2 Mn local moments. For low carrier densities, these valence band holes will be bound to the Mn ion, leading to shallow acceptor levels. This model of carrier-induced ferromagnetism is now fairly well established for (Ga,Mn)As as a result of electron paramagnetic resonance experiments [7], xray magnetic circular dichroism measurements [8,9], and magneto-transport data [10-13].The acceptor impurity levels of Fe and Co [2,3,6,4] are unlikely to lead to high valence band hole concentrations in arsenides or antimonides, as shown in Fig. 1. The possible coexistence of acceptor and neutral magnetic impurities suggests that a ferromagnetic double-exchange mechanism can dominate ...

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Electronic structures of III–V based ferromagnetic semiconductors: half-metallic phase

Cited by 92 publications

References 7 publications

Hole -character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches – Newly found spin-unpolarized gap states of s-type below 1 of Mn

Hole -character and delocalization in (Ga,Mn)As revised with pSIC and MLWF approaches – Newly found spin-unpolarized gap states of s-type below 1 of Mn

Optical properties of diluted magnetic semiconductors in coherent potential approximation

Theoretical Models of Ferromagnetic III‐V Semiconductors

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