Atomic-orbital-based approximate self-interaction correction scheme for molecules and solids

Pemmaraju, C. D.; Archer, Thomas; Sánchez‐Portal, Daniel; Sanvito, Stefano

doi:10.1103/physrevb.75.045101

Cited by 173 publications

(240 citation statements)

References 100 publications

(218 reference statements)

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“…The α-parameter empirically describes the charge screening in the given chemical environment. In metals with very good screening α vanishes, while for highly ionic compounds with poor screening such as NaCl, a value of α close to unity reproduces the experimental band gap 25 . For III-V and II-VI semiconductors as well as transition-metal oxides, the appropriate value of α is shown to be typically around one half 25 .…”

Section: Introductionmentioning

confidence: 67%

“…In metals with very good screening α vanishes, while for highly ionic compounds with poor screening such as NaCl, a value of α close to unity reproduces the experimental band gap 25 . For III-V and II-VI semiconductors as well as transition-metal oxides, the appropriate value of α is shown to be typically around one half 25 . A central question regarding the ASIC methodology itself is how it compares to the other beyond semi-local DFT methods, and then whether a single value of α can be used to reasonably accurately describe a number of key properties of all the different titanium oxides.…”

Section: Introductionmentioning

confidence: 67%

“…These titanium oxide phases cover a broad range of electronic properties, from metal (HT-Ti 4 O 7 ) to narrow-gap semiconductor 23,24 (band gap~0.1-0.2 eV, LT-Ti 4 O 7 and Ti 2 O 3 ) and to insulator 11,24 (band gap~3 eV, rutile TiO 2 ). In our work, we used the atomic-orbital-based self-interaction correction (ASIC) scheme 25,26 . The amount of self-interaction correction is controlled by a single parameter, α, which lies between 0 and 1 (for α=1 the full self-interaction correction is added, while for α=0 no correction is added).…”

Section: Introductionmentioning

confidence: 99%

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Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

et al. 2015

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Understanding electronic properties of sub-stoichiometric phases of titanium oxide such as Magnéli phase Ti 4 O 7 is crucial in designing and modeling resistive switching devices. Here we present our study on Magnéli phase Ti 4 O 7 together with rutile TiO 2 and Ti 2 O 3 using density functional theory methods with atomic-orbital-based self-interaction correction (ASIC). We predict a new antiferromagnetic ground state in the low temperature phase (or LT phase), and we explain energy difference with a competing antiferromagnetic state using a Heisenberg model. The predicted energy ordering of these states in the LT phase is calculated to be robust in a wide range of modeled isotropic strain. We have also investigated the dependence of the electronic structures of the Ti-O phases on stoichiometry. The splitting of titanium t 2g orbitals is enhanced with increasing oxygen deficiency as Ti-O is reduced. The electronic properties of all these phases can be reasonably well described by applying ASIC with a 'standard' value for transition metal oxides of the empirical parameter α of 0.5 representing the magnitude of the applied self-interaction correction.

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Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

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Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

et al. 2015

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“…This is particularly critical in the case of molecular junctions, where the system can be considerably large due to the presence of the metal electrodes. Therefore, different alternative approaches and corrections have been proposed to improve the description of the energy level alignment, for instance, corrections for self-interaction (SI) errors, 13,58 scissor operator (SCO) schemes 35,48,52,59,60 and constrained-DFT (CDFT). 61 In the present work we investigate, by means of total energy DFT and quantum transport calculations, the stability and conductivity of thiol and thiolate molecular junctions.…”

Section: Introductionmentioning

confidence: 99%

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

et al. 2014

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It is often assumed that the hydrogen atoms in the thiol groups of a benzene-1,4-dithiol dissociate when Au-benzene-1,4-dithiol-Au junctions are formed. We demonstrate, by stability and transport property calculations, that this assumption cannot be made. We show that the dissociative adsorption of methanethiol and benzene-1,4-dithiol molecules on a flat Au(111) surface is energetically unfavorable and that the activation barrier for this reaction is as high as 1 eV. For the molecule in the junction, our results show, for all electrode geometries studied, that the thiol junctions are energetically more stable than their thiolate counterparts. Due to the fact that density functional theory (DFT) within the local density approximation (LDA) underestimates the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital by several electron-volts, and that it does not capture the renormalization of the energy levels due to the image charge effect, the conductance of the Au-benzene-1,4-dithiol-Au junctions is overestimated. After taking into account corrections due to image charge effects by means of constrained-DFT calculations and electrostatic classical models, we apply a scissor operator to correct the DFT energy level positions, and calculate the transport properties of the thiol and thiolate molecular junctions as a function of the electrode separation. For the thiol junctions, we show that the conductance decreases as the electrode separation increases, whereas the opposite trend is found for the thiolate junctions. Both behaviors have been observed in experiments, therefore pointing to the possible coexistence of both thiol and thiolate junctions. Moreover, the corrected conductance values, for both thiol and thiolate, are up to two orders of magnitude smaller than those calculated with DFT-LDA.This brings the theoretical results in quantitatively good agreement with experimental data.

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“…[55][56][57] These selfinteraction errors are small for materials with delocalized electronic states, but can be significant in systems with lo- Note that only the valence bands are corrected since the empty conduction bands, derived from orbitals where the occupation numbers are close to zero, are not selfinteracting. This is in contrast to the LSDA+ U method, in which the occupied bands are lowered in energy and the unoccupied bands raised.…”

Section: Self-interaction Correctionsmentioning

confidence: 99%

Electronic properties of bulk and thin filmSrRuO3: Search for the metal-insulator transition

et al. 2008

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We calculate the properties of the 4d ferromagnet SrRuO 3 in bulk and thin film form with the aim of understanding the experimentally observed metal-to-insulator transition at reduced thickness. Although the spatial extent of the 4d orbitals is quite large, many experimental results have suggested that electron-electron correlations play an important role in determining this material's electronic structure. In order to investigate the importance of correlation, we use two approaches which go beyond the conventional local-density approximation to density-functional theory ͑DFT͒: the local spin-density approximation+ Hubbard U ͑LSDA+ U͒ and the pseudopotential self-interaction correction ͑pseudo-SIC͒ methods. We find that the details of the electronic structure predicted with the LSDA do not agree with the experimental spectroscopic data for bulk and thin film SrRuO 3 . Improvement is found by including electron-electron correlations, and we suggest that bulk orthorhombic SrRuO 3 is a moderately correlated ferromagnet whose electronic structure is best described by a 0.6 eV on-site Hubbard term, or equivalently with corrections for the self-interaction error. We also perform ab initio transport calculations that confirm that SrRuO 3 has a negative spin polarization at the Fermi level, due to the position of the minority Ru 4d band center. Even with static correlations included in our calculations we are unable to reproduce the experimentally observed metal-insulator transition, suggesting that the electronic behavior of SrRuO 3 ultrathin films might be dominated by extrinsic factors, such as surface disorder and defects, or due to dynamic spin correlations which are not included in our theoretical methods.

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Atomic-orbital-based approximate self-interaction correction scheme for molecules and solids

Cited by 173 publications

References 100 publications

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

Electronic properties of bulk and thin filmSrRuO3: Search for the metal-insulator transition

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