Magnetic frustration, short-range correlations and the role of the paramagnetic Fermi surface of PdCrO2

Billington, David P.; Ernsting, David; Millichamp, Thomas E.; Lester, C.; Dugdale, Stephen B; Kersh, David; Duffy, J. A.; Giblin, Sean; Taylor, Jonathan; Manuel, Pascal; Khalyavin, D. D.; Takatsu, Hiroshi

doi:10.1038/srep12428

Cited by 35 publications

(53 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It would be interesting to see how these data can be reconciled with the Compton scattering data of Ref. [26]. is as yet no experimental data to test this.…”

Section: Fermi Surface Of Pdcro2 Above and Below Tnmentioning

confidence: 90%

“…In PdCrO2, however, the issue is fundamental. Simple electron counting in the absence of correlation would say that the Fermi level should now sit in narrow Cr--derived bands, something confirmed in an explicit calculation [26]. Ionic considerations, however, say that Cr 3+ should be in a spin--3/2 state due to on--site correlation, have a large local moment in real PdCrO2 and that the CrO2 layers should be correlated electron insulators.…”

Section: Basic Features Of Electronic Structurementioning

confidence: 90%

“…PdCrO2 in its paramagnetic state to have a conduction band of the same character as that in PdCoO2, most experimental evidence says that it does (I note that a different interpretation is proposed in Ref. [26]). These observations imply that the Cr--O layer is a Mott insulator.…”

Section: Although Electron Counting or Standard Band Theory Would Notmentioning

confidence: 99%

See 2 more Smart Citations

The properties of ultrapure delafossite metals

2017

View full text Add to dashboard Cite

Although they were first synthesized in chemistry laboratories nearly fifty years ago, the physical properties of the metals PdCoO, PtCoO and PdCrO have only more recently been studied in detail. The delafossite structure contains triangular co-ordinated atomic layers, and electrical transport in the delafossite metals is strongly 2D. Their most notable feature is their in-plane conductivity, which is amazingly high for oxide metals. At room temperature, the conductivity of non-magnetic PdCoO and PtCoO is higher per carrier than those of any alkali metal and even the most conductive elements, copper and silver. At low temperatures the best crystals have resistivities of a few nΩ cm, corresponding to mean free paths of tens of microns. PdCrO is a frustrated antiferromagnetic metal, with magnetic scattering contributing to the resistivity at high temperatures and small gaps opening in the Fermi surface below the Néel temperature. There is good evidence that electronic correlations are weak in the Pd/Pt layers but strong in the Co/Cr layers; indeed the Cr layer in PdCrO is thought to be a Mott insulator. The delafossite metals therefore act like natural heterostructures between strongly correlated and nearly free electron sub-systems. Combined with the extremely high conductivity, they provide many opportunities to study electrical transport and other physical properties in new regimes. The purpose of this review is to describe current knowledge of these fascinating materials and set the scene for what is likely to be a considerable amount of future research.

show abstract

“…It would be interesting to see how these data can be reconciled with the Compton scattering data of Ref. [26]. is as yet no experimental data to test this.…”

Section: Fermi Surface Of Pdcro2 Above and Below Tnmentioning

confidence: 90%

Section: Basic Features Of Electronic Structurementioning

confidence: 90%

See 1 more Smart Citation

The properties of ultrapure delafossite metals

2017

View full text Add to dashboard Cite

show abstract

“…Very rarely, the Fermi surface contribution to the directional differences is readily visible in the data (see, for example, Billington et al . 36 ,). However, our calculations confirm that the Fermi surface contribution to the Compton profile anisotropy for stoichiometric MgCNi 3 is small, the anisotropy being dominated by the fully occupied bands.…”

Section: Resultsmentioning

confidence: 99%

Vacancies, disorder-induced smearing of the electronic structure, and its implications for the superconductivity of anti-perovskite MgC0.93Ni2.85

Ernsting

Billington

Millichamp

et al. 2017

Sci Rep

Self Cite

View full text Add to dashboard Cite

The anti-perovskite superconductor MgC0.93Ni2.85 was studied using high-resolution x-ray Compton scattering combined with electronic structure calculations. Compton scattering measurements were used to determine experimentally a Fermi surface that showed good agreement with that of our supercell calculations, establishing the presence of the predicted hole and electron Fermi surface sheets. Our calculations indicate that the Fermi surface is smeared by the disorder due to the presence of vacancies on the C and Ni sites, but does not drastically change shape. The 20% reduction in the Fermi level density-of-states would lead to a significant (~70%) suppression of the superconducting T c for pair-forming electron-phonon coupling. However, we ascribe the observed much smaller T c reduction at our composition (compared to the stoichiometric compound) to the suppression of pair-breaking spin fluctuations.

show abstract

“…27 To put this into context, in related layered triangular lattices frustration indexes as low as 1.3 and as high as 13 have been reported. 19,28,29 It should be noted, however, that care needs to be taken when making direct comparisons of f or using it explicitly as evidence of frustration since it is greatly influenced by nearest neighbour interactions and dimensionality. 24 Slight deviations between the zero field cooled and field cooled data are evident below T N suggesting the possibility of weak ferromagnetic interactions or spin glass-like behaviour.…”

Section: Resultsmentioning

confidence: 99%