Separating different contributions to the crystal-field parameters using Wannier functions

Scaramucci, Andrea; Ammann, Jeanine; Spaldin, Nicola A.; Ederer, Claude

doi:10.1088/0953-8984/27/17/175503

Cited by 16 publications

(23 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Ref. [20], it was suggested to use this freedom to estimate different contributions to the ligand field splitting of a given set of orbitals. For instance, if one is interested in the splitting of the valence d orbitals of…”

Section: A Wannierization and Crystal Field Parametersmentioning

confidence: 99%

See 1 more Smart Citation

Crystal field, ligand field, and interorbital effects in two-dimensional transition metal dichalcogenides across the periodic table

Pasquier

Yazyev

2019

2D Mater.

View full text Add to dashboard Cite

Two-dimensional transition metal dichalcogenides (TMDs) exist in two polymorphs, referred to as 1T and 1H, depending on the coordination sphere of the transition metal atom. The broken octahedral and trigonal prismatic symmetries lead to different crystal and ligand field splittings of the d electron states, resulting in distinct electronic properties. In this work, we quantify the crystal and ligand field parameters of two-dimensional TMDs using a Wannier-function approach. We adopt the methodology proposed by Scaramucci et al. [A. Scaramucci et al., J. Phys.: Condens. Matter 27, 175503 (2015)]. that allows to separate various contributions to the ligand field by choosing different manifolds in the construction of the Wannier functions. We discuss the relevance of the crystal and ligand fields in determining the relative stability of the two polymorphs as a function of the filling of the d-shell. Based on the calculated parameters, we conclude that the ligand field, while leading to a small stabilizing factor for the 1H polymorph in the d 1 and d 2 TMDs, plays mostly an indirect role and that hybridization between different d orbitals is the dominant feature. We investigate trends across the periodic table and interpret the variations of the calculated crystal and ligand fields in terms of the change of charge-transfer energy, which allows developing simple chemical intuition. arXiv:1810.01302v1 [cond-mat.mes-hall]

show abstract

Section: A Wannierization and Crystal Field Parametersmentioning

confidence: 99%

“…Indeed, the on-site energies of some of the d WFs are shifted upward in energy compared to the spd model, as we summarize in Table II. The differences of on-site energies between the spd and pd models can be interpreted as the hybridization energy between s and d orbitals [20].…”

Section: The Case Of Tas2mentioning

confidence: 99%

Crystal field, ligand field, and interorbital effects in two-dimensional transition metal dichalcogenides across the periodic table

Pasquier

Yazyev

2019

2D Mater.

View full text Add to dashboard Cite

show abstract

“…Bloch states in the periodic solids are characterized by a band index m and a wave vector k in the first Brillouin zone (FBZ). The many body Hamiltonian is diagonal in this basis [33]:…”

Section: Anomalous Crystal Field Splittingmentioning

confidence: 99%

“…Using this feature we can construct three different sets of Wannier functions (TB models) corresponding to : (i) 'd-model'-only effective Fe-d orbitals, (ii) 'dp-model' containing Fe-d orbitals and Asp orbitals, and (iii) 'dps-model' containing Fe-d orbitals, As-p orbitals, Li/Na-s orbitals. The onsite energy difference, obtained using different orbital projections, can be interpreted as decomposition of the total crystal field splitting [33].…”

Section: Anomalous Crystal Field Splittingmentioning

confidence: 99%

See 1 more Smart Citation

Pressure induced Lifshitz transition and anomalous crystal field splitting in AFeAs (A=Li/Na) Fe-based superconducting compounds: A first principles study

Ghosh¹,

Ghosh²

2021

Preprint

View full text Add to dashboard Cite

The effect of hydrostatic pressure on the electronic structures of iron pnictide superconducting compounds LiFeAs and NaFeAs through density functional theory based first principles studies are presented, using the predicted crystal structures at very high pressure by Zhang et al.[1]. The orbital selective pressure induced modifications in the partial density of states and electronic band structures reveal mixed multi-band multi-orbital nature of these compounds, with energetically degenerate dxz/dyz orbitals at ambient pressure. Due to larger hydrostatic pressures some of the electron/hole bands crosses the Fermi level, leading to significant topological modifications in Fermi surfaces known as Lifshitz transition. Interrelation between Lifshitz transition and superconductivity-an important subject matter of current research are described. Based on such interconnection the current study predicts the superconducting-Tc in 111 compounds can not be raised at such high pressures. Wannier functions based electronic structure investigation reveal a relatively larger hybridization between the Fe-3d and As-4p orbitals at higher pressures, as an effect of which the orbital degeneracy of dxz and dyz orbitals are lifted. Different hybridization contributions in the crystal-field splitting are separated using the Wannier functions based formalism, by incorporating different bands with a particular orbital character in the Wannier function construction. Pressure dependence of the intra/inter orbital hopping amplitudes between Fe-d orbitals has been discussed using low energy tight binding model.

show abstract

Pressure-induced collapsed tetragonal transition in optimally Na-doped $${\text{CaFe}}_{2} {\text{As}}_{2}$$

Pokhriyal,

Ghosh

2024

J Mater Sci

View full text Add to dashboard Cite

A comprehensive first-principles study on electronic structure of optimally doped $${\hbox {Ca}_{0.33}\hbox {Na}_{0.67}\hbox {Fe}_2\hbox {As}_2}$$ Ca 0.33 Na 0.67 Fe 2 As 2 under hydrostatic pressures in the presence of magnetic configurations is presented. A magneto-structural transition from a tetragonal to a collapsed tetragonal phase at 3 GPa hydrostatic pressure is predicted in double-stripe antiferromagnetic configuration that corroborates experimental observations. As the system enters the non-superconducting collapsed phase, significant deviations occur in the local structural parameters compared to those at optimal $${\it{T}}_{c}$$ T c values. This transition coincides with a sharp decrease in As density of states (DOS), accompanied by Fe magnetic moment collapse and substantial Fe square plane charge density modification. The structural transition induces a comprehensive reconstruction of the electronic structure, marked by distorted $$\hbox {FeAs}_{4}$$ FeAs 4 tetrahedra, potentially leading to unfavourable nesting conditions, and complete suppression of magnetism, correlating with the observed disappearance of superconductivity. Increasing pressure leads to a rise in crystal field splitting, influencing the spin-state transition in $${\hbox {Ca}_{0.33}\hbox {Na}_{0.67}\hbox {Fe}_2\hbox {As}_2}$$ Ca 0.33 Na 0.67 Fe 2 As 2 , ultimately resulting in a shift from tetragonal to non-magnetic collapsed tetragonal phase as the $$\hbox {Fe}^{2+}$$ Fe 2 + spin state transitions to a low spin state. This demonstrates the intricate interplay between crystal field splitting, external pressure, and spin dynamics, highlighting the significant impact of magneto-volume effects on the structural phase of material under pressure.

show abstract

Separating different contributions to the crystal-field parameters using Wannier functions

Cited by 16 publications

References 36 publications

Crystal field, ligand field, and interorbital effects in two-dimensional transition metal dichalcogenides across the periodic table

Crystal field, ligand field, and interorbital effects in two-dimensional transition metal dichalcogenides across the periodic table

Pressure induced Lifshitz transition and anomalous crystal field splitting in AFeAs (A=Li/Na) Fe-based superconducting compounds: A first principles study

Pressure-induced collapsed tetragonal transition in optimally Na-doped $${\text{CaFe}}_{2} {\text{As}}_{2}$$

Contact Info

Product

Resources

About