Chemical potentials and workfunctions of metal surfaces in the theory of an inhomogeneous electron gas

Schulte, Florian

doi:10.1088/0022-3719/7/20/003

Cited by 28 publications

(10 citation statements)

References 6 publications

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“…The effect of the correlation potential is most obvious in the work function, obtained from the KS Fermi energy of the slab relative to the electrostatic potential in the middle of the vacuum region. 34,35 Table I lists the LDA and GGA work functions, both including and without correlation (for the GGA the PBEsol form 36 has been applied). The LDA and GGA values are in good agreement with the [38][39][40][41] given the dependence of the work function on a and the various other technical parameters.…”

Section: Comparison Of Exx and Lda Resultsmentioning

confidence: 99%

Exact exchange plane-wave-pseudopotential calculations for slabs

Engel

2014

The Journal of Chemical Physics

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The exact exchange of density functional theory is applied to both free-standing graphene and a Si(111) slab, using the plane-wave pseudopotential (PWPP) approach and a periodic repetition of the supercell containing the slab. It is shown that (i) PWPP calculations with exact exchange for slabs in supercell geometry are basically feasible, (ii) the width of the vacuum required for a decoupling of the slabs is only moderately larger than in the case of the local-density approximation, and (iii) the resulting exchange potential vx shows an extended region, both far outside the surface of the slab and far from the middle of the vacuum region between the slabs, in which vx behaves as -e(2)/z, provided the width of the vacuum is chosen sufficiently large. This last result is corroborated by an analytical analysis of periodically repeated jellium slabs. The intermediate -e(2)/z behavior of vx can be used for an absolute normalization of vx and the total Kohn-Sham potential, which, in turn, allows the determination of the work function.

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Section: Comparison Of Exx and Lda Resultsmentioning

confidence: 99%

Exact exchange plane-wave-pseudopotential calculations for slabs

Engel

2014

The Journal of Chemical Physics

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“…Besides, the only energy of the full KS spectrum which has a physical significance is precisely the energy of the highest occupied level, which can be identified with . 52 The work function for a slab with r s = 2.07 and d =4 F is shown schematically in Fig. 1.…”

Section: Work Functionmentioning

confidence: 99%

Exact-exchange Kohn-Sham potential, surface energy, and work function of jellium slabs

2008

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Exact-exchange self-consistent calculations of the Kohn-Sham potential, surface energy, and work function of jellium slabs are reported in the framework of the optimized effective potential ͑OEP͒ scheme of density functional theory. In the vacuum side of the jellium surface and at a distance z that is larger than the slab thickness, the exchange-only Kohn-Sham potential is found to be imagelike ͑ϳ−e 2 / z͒ but with a coefficient that differs from that of the classical image potential V im ͑z͒ =−e 2 / 4z. The three OEP contributions to the surface energy ͑kinetic, electrostatic, and exchange͒ are found to oscillate as a function of the slab thickness, as occurs in the case of the corresponding calculations based on the use of single-particle orbitals and energies obtained in the local-density approximation ͑LDA͒. The OEP work function presents large quantum size effects that are absent in the LDA and which reflect the intrinsic derivative discontinuity of the exact Kohn-Sham potential.

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“…The former definition is appropriate for slab calculations where a vacuum region is explicitly included in the model. Thus, the work function is most commonly evaluated by 72,73 …”

Section: Work Functionmentioning

confidence: 99%

Modeling bulk and surface Pt using the “Gaussian and plane wave” density functional theory formalism: Validation and comparison to k-point plane wave calculations

Santarossa¹,

Vargas²,

Iannuzzi³

et al. 2008

The Journal of Chemical Physics

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We present a study on structural and electronic properties of bulk platinum and the two surfaces (111) and (100) comparing the Gaussian and plane wave method to standard plane wave schemes, normally employed for density functional theory calculations on metallic systems. The aim of this investigation is the assessment of methods based on the expansion of the Kohn-Sham orbitals into localized basis sets and on the supercell approach, in the description of the metallicity of Pt. Electronic structure calculations performed at Gamma-point only on supercells of different sizes, from 108 up to 864 atoms, are compared to the results obtained for the unit cell of four Pt atoms where the k-point expansion of the wave function over Monkhorst-Pack grids up to (10x10x10) has been employed. The evaluation of the two approaches with respect to bulk properties is done through the calculation of the equilibrium lattice constant, the bulk modulus, and the total and the d-projected density of states. For the Pt(111) and Pt(100) surfaces, we consider the relaxation of the first layers, the surface energies, the work function, the total density of states, as well as the center and filling of the d bands. Our results confirm that the accuracy of two approaches in the description of electronic and structural properties of Pt is equivalent, providing that consistent supercells and k-point meshes are used. Moreover, we estimate the supercell size that can be safely adopted in the Gaussian and plane wave method in order to obtain the same reliability of previous theoretical studies based on well converged plane wave calculations available in literature. The latter studies, in turn, set the level of agreement with experimental data. In particular, we obtain excellent agreement in the evaluation of the density of states for either bulk and surface systems, and our data are also in good agreement with previous works on Pt reported in literature. We conclude that Gaussian and plane wave calculations, with simulation cells of 400-800 atoms, can be safely used in the study of chemistry related problems involving transition metal surfaces. We present a study on structural and electronic properties of bulk platinum and the two surfaces ͑111͒ and ͑100͒ comparing the Gaussian and plane wave method to standard plane wave schemes, normally employed for density functional theory calculations on metallic systems. The aim of this investigation is the assessment of methods based on the expansion of the Kohn-Sham orbitals into localized basis sets and on the supercell approach, in the description of the metallicity of Pt. Electronic structure calculations performed at ⌫-point only on supercells of different sizes, from 108 up to 864 atoms, are compared to the results obtained for the unit cell of four Pt atoms where the k-point expansion of the wave function over Monkhorst-Pack grids up to ͑10ϫ 10ϫ 10͒ has been employed. The evaluation of the two approaches with respect to bulk properties is done through the calculation of the equilibrium latt...

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Chemical potentials and workfunctions of metal surfaces in the theory of an inhomogeneous electron gas

Cited by 28 publications

References 6 publications

Exact exchange plane-wave-pseudopotential calculations for slabs

Exact exchange plane-wave-pseudopotential calculations for slabs

Exact-exchange Kohn-Sham potential, surface energy, and work function of jellium slabs

Modeling bulk and surface Pt using the “Gaussian and plane wave” density functional theory formalism: Validation and comparison to k-point plane wave calculations

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