Computational band-structure engineering of III–V semiconductor alloys

Geller, Clint B.; Wolf, W.; Picozzi, Silvia; Continenza, A.; Asahi, Ryoji; Mannstadt, W.; Freeman, Arthur J; Wimmer, E.

doi:10.1063/1.1383282

Cited by 102 publications

(53 citation statements)

References 16 publications

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“…Because LDA underestimates the oxide band gaps and may give incorrect energy location of the states of different cations in the conduction band of multicomponent materials, we also employed the self-consistent screenedexchange LDA (sX-LDA) method [20,[24][25][26][27] for more accurate description of the band gap values and the valence/conduction band states of the twelve complex oxides. For the sX-LDA calculations, cutoff for the plane wave basis was 10.2 Ry and summations over the Brillouin zone were carried out using at least 14 special k points in the irreducible wedge.…”

Section: Methods and Approximationsmentioning

confidence: 99%

Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

Murat

Medvedeva

2012

Phys. Rev. B

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The structural, electronic, and optical properties of twelve multicomponent oxides with layered structure, RAMO4, where R 3+ =In or Sc; A 3+ =Al or Ga; and M 2+ =Ca, Cd, Mg, or Zn, are investigated using first-principles density functional approach. The compositional complexity of RAMO4 leads to a wide range of band gap values varying from 2.45 eV for InGaCdO4 to 6.29 eV for ScAlMgO4 as obtained from our self-consistent screened-exchange local density approximation calculations. Strikingly, despite the different band gaps in the oxide constituents, namely, 2-4 eV in CdO, In2O3, or ZnO; 5-6 eV for Ga2O3 or Sc2O3; and 7-9 eV in CaO, MgO, or Al2O3, the bottom of the conduction band in the multicomponent oxides is formed from the s-states of all cations and their neighboring oxygen p-states. We show that the hybrid nature of the conduction band in multicomponent oxides originates from the unusual five-fold atomic coordination of A 3+ and M 2+ cations which enables the interaction between the spatially-spread s-orbitals of adjacent cations via shared oxygen atoms. The effect of the local atomic coordination on the band gap, the electron effective mass, the orbital composition of the conduction band, and the expected (an)isotropic character of the electron transport in layered RAMO4 is thoroughly discussed.

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Section: Methods and Approximationsmentioning

confidence: 99%

Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

Murat

Medvedeva

2012

Phys. Rev. B

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“…In our defect calculations, in addition to the bandgap correction via the screened-exchanged LDA method [38][39][40][41], we also address the band-edge and the finite-size supercell errors in the defect calculations. We employ the correction methods proposed by Lany and Zunger [42], namely, (i) shifting of shallow levels with the corresponding band edges of the host; (ii) band-filling correction; (iii) potential-alignment correction for supercells with charged defects; and (iv) image charge correction for charged defects via simplified Makov-Payne scheme [42].…”

Section: Approachmentioning

confidence: 99%

Composition-dependent oxygen vacancy formation in multicomponent wide-band-gap oxides

Murat

Medvedeva

2012

Phys. Rev. B

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The formation and distribution of oxygen vacancy in layered multicomponent InAM O4 oxides with A 3+ =Al or Ga, and M 2+ =Ca or Zn, and in the corresponding binary oxide constituents is investigated using first-principles density functional calculations. Comparing the calculated formation energies of the oxygen defect at six different site locations within the structurally and chemically distinct layers of InAM O4 oxides, we find that the vacancy distribution is significantly affected not only by the strength of the metal-oxygen bonding, but also by the cation's ability to adjust to anisotropic oxygen environment created by the vacancy. In particular, the tendency of Zn, Ga, and Al atoms to form stable structures with low oxygen coordination, results in nearly identical vacancy concentrations in the InO1.5 and GaZnO2.5 layers in InGaZnO4, and only an order of magnitude lower concentration in the AlZnO2.5 layer as compared to the one in the InO1.5 layer in InAlZnO4. The presence of two light metal constituents in the InAlCaO4 along with Ca failure to form a stable fourfold coordination as revealed by its negligible relaxation near the defect, leads to a strong preference of the oxygen vacancy to be in the InO1.5 layer. Based on the results obtained, we derive general rules on the role of chemical composition, local coordination, and atomic relaxation in the defect formation and propose an alternative light-metal oxide as a promising constituent of multicomponent functional materials with tunable properties.

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“…sX-LDA is a variational total energy method with an explicit screened exchange energy designed to improve over LDA. It has been shown to accurately reproduce both band gap and structural properties of many simple semiconductor binary compounds [22]. However, it has not been tested thoroughly for more complicated systems such as CaB 6 and the current study also serves as a test for sX-LDA itself.…”

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confidence: 99%

“…Encouraging results have been observed in many semiconductor materials with Eq. (2), yielding accurate band gaps and structural properties, both better than LDA results [21,22].…”

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confidence: 99%

Electronic structure of calcium hexaborides

Lee

Wang

2005

Applied Physics Letters

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We present a theoretical study of crystal and electronic structures of CaB 6 within a screenedexchange local density approximation (sX-LDA). Our ab initio total energy calculations show that CaB 6 is a semiconductor with a gap of > 1.2 eV, in agreement with recent experimental observations. We show a very sensitive band gap dependence on the crystal internal parameter, which might partially explain the scatter of previous theoretical results. Our calculation demonstrates that it is essential to study this system simultaneously for both crystal structures and electronic properties, and that the sX-LDA provides an ideal method for this problem.

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Computational band-structure engineering of III–V semiconductor alloys

Cited by 102 publications

References 16 publications

Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

Composition-dependent oxygen vacancy formation in multicomponent wide-band-gap oxides

Electronic structure of calcium hexaborides

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