Comments on "Band gap and band parameters of InN and GaN from quasiparticle energy calculations based on exact-exchange density-functional theory" [Appl. Phys. Lett. 89, 161919 (2006)] (original) (raw)
Related papers
2006
We have studied the electronic structure of InN and GaN employing G0W0 calculations based on exact-exchange density-functional theory. For InN our approach predicts a gap of 0.7 eV. Taking the Burnstein-Moss effect into account, the increase of the apparent quasiparticle gap with increasing electron concentration is in good agreement with the observed blue shift of the experimental optical absorption edge. Moreover, the concentration dependence of the effective mass, which results from the non-parabolicity of the conduction band, agrees well with recent experimental findings. Based on the quasiparticle band structure the parameter set for a 4 × 4 k•p Hamiltonian has been derived.
An oversight of several previous results from local density approximation (LDA) calculations appear to have led to an incomplete, and hence misleading, characterization of the capability of density functional theory (DFT) to describe correctly the electronic properties of wurtzite GaN (w-GaN) and InN (w-InN) [Phys. Rev. B 82, 115102 (2010)]. These comments are aimed at presenting a different picture of the above capability for DFT calculations that solve self-consistently the system of equations of DFT. They also underscore, in light of the experimentally established Burstein-Moss effect, the need to specify the carrier density when citing a band gap for w-InN.
Journal of Applied Physics, 2000
This work presents nonlocal pseudopotential calculations based on realistic, effective atomic potentials of the wurtzite phase of GaN, InN, and AlN. A formulation formulation for the model effective atomic potentials has been introduced. For each of the constitutive atoms in these materials, the form of the effective potentials is optimized through an iterative scheme in which the band structures are recursively calculated and selected features are compared to experimental and/or ab initio results. The optimized forms of the effective atomic potentials are used to calculate the band structures of the binary compounds, GaN, InN, and AlN. The calculated band structures are in excellent overall agreement with the experimental/ab initio values, i.e., the energy gaps at high-symmetry points, valence-band ordering, and effective masses for electrons match to within 3%, with a few values within 5%. The values of the energy separation, effective masses, and nonparabolicity coefficients for several secondary valleys are tabulated as well in order to facilitate analytical Monte Carlo transport simulations.
Calculated Electronic and Related Properties of Wurtzite and Zinc Blende Gallium Nitride (GaN)
We report calculated, electronic and related properties of wurtzite and zinc blende gallium nitrides (w-GaN, zb-GaN). We employed a local density approximation (LDA) potential and the linear combination of atomic orbital (LCAO) formalism. The implementation of this formalism followed the Bagayoko, Zhao, and Williams (BZW) method, as enhanced by Ekuma and Franklin (BZW-EF). The calculated electronic and related properties, for both structures of GaN, are in good agreement with corresponding, experimental data, unlike results from most previous ab initio calculations utilizing a density functional theory (DFT) potential. These results include the electronic energy bands, the total and partial densities of states (DOS and pDOS), and effective masses for both structures. The calculated band gap of 3.29 eV, for w-GaN, is in agreement with experiment and is an average of 1.0 eV larger than most previous ab-initio DFT results. Similarly, the calculated band gap of zb-GaN of 2.9 eV, for a r...
Physical Review B, 2001
A number of diverse bulk properties of the zinc-blende and wurtzite III-V nitrides AlN, GaN, and InN, are predicted from first principles within density-functional theory using the plane-wave ultrasoft pseudopotential method, within both the local density approximation ͑LDA͒ and generalized gradient approximation ͑GGA͒ to the exchange-correlation functional. Besides structure and cohesion, we study formation enthalpies ͑a key ingredient in predicting defect solubilities and surface stability͒, spontaneous polarizations and piezoelectric constants ͑central parameters for nanostructure modeling͒, and elastic constants. Our study bears out the relative merits of the two density-functional approaches in describing diverse properties of the III-V nitrides ͑and of the parent species N 2 , Al, Ga, and In͒. None of the two schemes gives entirely successful results. However, the GGA associated with the multiprojector ultrasoft pseudopotential method slightly outperforms the LDA overall as to lattice parameters, cohesive energies, and formation enthalpies of wurtzite nitrides. This is relevant to the study of properties such as polarization, vibrational frequencies, elastic constants, nonstochiometric substitution, and absorption. A major exception is the formation enthalpy of InN, which is underestimated by the GGA ͑ϳ0 vs Ϫ0.2 eV͒.
Physical Review B, 1999
We have performed density-functional calculations for III-V nitrides using the pseudopotential plane-wave method where the d states of the Ga and In atoms are included as valence states. Results obtained using both the local-density approximation ͑LDA͒ and the generalized gradient approximation ͑GGA͒ for the exchangecorrelation functional are compared. Bulk properties, including lattice constants, bulk moduli and derivatives, cohesive energies, and band structures are reported for AlN, GaN, and InN in zinc-blende and wurtzite structures. We also report calculations for some of the bulk phases of the constituent elements. The performance of our pseudopotentials and various convergence tests are discussed. We find that the GGA yields improved physical properties for bulk Al, N 2 , and bulk AlN compared to the LDA. For GaN and InN, essentially no improvement is found: the LDA exhibits overbinding, but the GGA shows a tendency for underbinding. The degree of underbinding and the overestimate of the lattice constant as obtained within the GGA increases on going from GaN to InN. Band structures are found to be very similar within the LDA and GGA. For the III-V nitrides, the GGA therefore does not offer any significant advantages; in particular, no improvement is found with respect to the band-gap problem. ͓S0163-1829͑99͒06107-X͔
physica status solidi (b), 2003
We investigate the electronic properties of the technologically important wide‐band‐gap semiconductor GaN employing ‘state‐of‐the‐art’ DFT‐LDA calculations using a FP‐LAPW code. The Ga 3d electrons are treated both as core or as valence electrons and the wurtzite as well as the zincblende modifications of GaN are investigated. In particular, we address the influence of the lattice configuration and of the d electrons to the electronic structure of w‐GaN and c‐GaN. Band structures, densities of states, orbital‐resolved densities of states, total and partial valence charge densities, and ionicity factors are analysed in great detail. The calculated values of the energy gaps, bandwidths, spin–orbit, crystal‐field splittings, and the correct band degeneracies are compared to experimental and/or ab initio results. Several features of w‐GaN resemble those of c‐GaN. Most of the calculated band parameters, of band gaps, total and upper‐valence bandwidths, and antisymmetric gap for w‐GaN are...
Local-density-approximation prediction of electronic properties of GaN, Si, C, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">mml:mrowmml:msubmml:mrow<mml:mi mathvariant="normal">RuOmml:mrowmml:mn2</mml:mro...
Physical review, 1999
We present calculated electronic properties of gallium nitride ͑GaN͒, silicon ͑Si͒, diamond ͑C͒, and ruthenium dioxide (RuO 2). We implemented a simple computational procedure that avoids a recently identified basis set and variational effect. This effect, inherent to the use of basis sets in variational calculations, is believed to have affected ab initio calculations of electronic properties of semiconductors since their inception. We employed ab initio, density-functional calculations using a local-density-approximation potential and the linear combination of atomic orbital formalism. There is an excellent agreement between our findings and experimental results. In particular, the calculated, direct, minimum band gap of GaN, for low temperatures, is 3.2 eV, while the practical band gap, as per the calculated density of states, is 3.40 eV. Band gaps and excitation energies for silicon and diamond compare favorably with experimental results. ͓S0163-1829͑99͒11727-2͔
Electronic band structure pseudopotential calculation of wurtzite III-nitride materials
2006
The electronic properties of the wurtzite III-nitride compound semiconductors GaN, InN and AlN are studied within the empirical pseudopotential approach. An analytical function for both symmetric and antisymmetric parts of the pseudopotential with adjustable coefficients has been reported. Using this model the selected features of these materials such as energy gap, bandwidth, crystal-field splitting energy, Luttinger-like parameters, and effective masses are calculated and compared to experimental and recently published theoretical results and the comparisons show a good agreement. r 2005 Published by Elsevier B.V.
FP-LAPW calculations of ground state properties for AlN, GaN and InN compounds
We present first-principals all-electrons total-energy calculations concerning structural and electronic properties for the group III-V zinc-blend-like compounds AlN, GaN and InN using the full-potential linearized augmented plane wave (FP-LAPW) approach within the density functional theory (D.F.T) in the local density approximation (L.D.A) and the generalized gradient approximation (G.G.A) for the exchange correlations functional. Moreover, we have calculated bulk properties, including ground-state energies, lattice parameters, bulk modulus, its derivatives, cohesive energy and band structures. We find that the GGA yields improved physical properties for bulk AlN compared to the LDA. For GaN and InN, essentially no improvement is found: the LDA exhibits over binding, whereas the GGA shows a tendency for under binding. The degree of under binding and the overestimation of lattice parameters as obtained within the GGA increase on going from InN to GaN. Band structures are found to be very similar within the LDA and the GGA, for AlN, GaN and InN, therefore, the GGA does not offer any significant advantages.