The<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>α</mml:mi><mml:mo>→</mml:mo><mml:mi>γ</mml:mi></mml:math>Transition in Ce: A Theoretical View from Optical Spectroscopy

Haule, Kristjan; Oudovenko, V. S.; Savrasov, S. Y.; Kotliar, Gabriel

doi:10.1103/physrevlett.94.036401

Cited by 123 publications

(110 citation statements)

References 25 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…LDA+DMFT calculations 41,42,43,44,45,46 have consistently supported the KVC scenario 25,26,27,28 for Ce. They show, e.g., a rapid build up of the Kondo resonance for volume reduced across the γ-α two-phase region, which is taken as a signature of the onset of screening.…”

Section: Resultsmentioning

confidence: 81%

“…41,42,43,44,45,46 Such calculations for Ce also point to ongoing 4f delocalization in the relevant volume range, a critical driver of Mott transitions. 42,43 To further clarify the behavior of the compressed trivalent rare earths, the present paper reports LDA+DMFT calculations of the 4f spin and charge susceptibilities and the 4f n , 4f n±1 configuration weights for the first three members, Ce (n = 1), Pr (n = 2), and Nd (n = 3).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Screening of4fmoments and delocalization in the compressed light rare earths

2009

View full text Add to dashboard Cite

Spin and charge susceptibilities and the 4f n , 4f n−1 , and 4f n+1 configuration weights are calculated for compressed Ce (n = 1), Pr (n = 2), and Nd (n = 3) metals using dynamical mean field theory combined with the local-density approximation. At ambient and larger volumes these trivalent rare earths are pinned at sharp 4f n configurations, their 4f moments assume atomic-limiting values, are unscreened, and the 4f charge fluctuations are small indicating little f state density near the Fermi level. Under compresssion there is dramatic screening of the moments and an associated increase in both the 4f charge fluctuations and static charge susceptibility. These changes are coincident with growing weights of the 4f n−1 configurations, which it is argued are better measures of delocalization than the 4f n+1 weights which are compromised by an increase in the number of 4f electrons caused by rising 6s, 6p bands. This process is continuous and prolonged as a function of volume, with strikingly similarity among the three rare earths, aside from the effects moderating and shifting to smaller volumes for the heavier members. The observed α-γ collapse in Ce occurs over the large-volume half of this evolution, the Pr analog at smaller volumes, and Nd has no collapse.

show abstract

Section: Resultsmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Screening of4fmoments and delocalization in the compressed light rare earths

2009

View full text Add to dashboard Cite

show abstract

“…This fact is clearly indicated, e.g., by the photoemission spectra, which is known experimentally [6][7][8] and theoretically [9][10][11]. Despite this similarity, there is a key difference between these two models: while the KVC attributes a very important role to the interplay between the localized 4f orbitals and the itinerant spd conduction bands, the itinerant electrons are "spectators" in the HM picture.The development of LDA+DMFT (Local Density Approximation plus Dynamical Mean Field Theory) [12] results [13][14][15] has successfully reproduced many aspects of this transition, and different aspects of these studies can be understood in both physical pictures. There are still fundamental questions which have not been answered.…”

mentioning

confidence: 99%

“…The development of LDA+DMFT (Local Density Approximation plus Dynamical Mean Field Theory) [12] results [13][14][15] has successfully reproduced many aspects of this transition, and different aspects of these studies can be understood in both physical pictures. There are still fundamental questions which have not been answered.…”

mentioning

confidence: 99%

γ−αIsostructural Transition in Cerium

et al. 2013

Self Cite

View full text Add to dashboard Cite

Below the critical temperature Tc ≃ 600K, an iso-structural transition, named γ-α transition, can be induced in Cerium by applying pressure. This transition is first-order, and is accompanied by a sizable volume collapse. A conclusive theoretical explanation of this intriguing phenomenon has still not been achieved, and the physical pictures proposed so far are still under debate. In this work, we illustrate zero-temperature first-principle calculations which clearly demonstrate that the γ-α transition is induced by the interplay between the electron-electron Coulomb interaction and the spin-orbit coupling. We address the still unresolved problem on the existence of a second low-T critical point, i.e., whether the energetic effects alone are sufficient or not to induce the γ-α transition at zero temperature.The γ-α iso-structural transition in Cerium [1] was discovered in 1949 [2]. Since then, a lot of theoretical and experimental work has been devoted to its understanding. The great interest in this phenomenon arises from the fact that the transition is isostructural, i.e., the lattice structure of the system is equal in the two phases. Furthermore, the possibility that the underlying mechanism lies in the electronic structure only -i.e., without it being necessary to involve other effects -makes Cerium a potential theoretical testing ground for basic concepts of correlated electron systems. Two main theoretical pictures are still under debate to explain the volume collapse: the Kondo volume collapse (KVC) [3,4] and the orbital-selective Mott transition within the Hubbard model (HM) [5]. According to the KVC the transition is induced by the rapid change of the coherence temperature across the transition boundaries, which affect dramatically the structure of the conduction spd electrons through Kondo effect. According to the HM, instead, it is the hopping between f orbitals that changes drastically across the transition between the α phase (with delocalized f electrons) and the γ phase (with localized f electrons), as for the Mott transition in the Hubbard model.Consistently with both the HM and the KVC pictures, the f -electrons are strongly correlated both in the α and in the γ phase. This fact is clearly indicated, e.g., by the photoemission spectra, which is known experimentally [6][7][8] and theoretically [9][10][11]. Despite this similarity, there is a key difference between these two models: while the KVC attributes a very important role to the interplay between the localized 4f orbitals and the itinerant spd conduction bands, the itinerant electrons are "spectators" in the HM picture.The development of LDA+DMFT (Local Density Approximation plus Dynamical Mean Field Theory) [12] results [13][14][15] has successfully reproduced many aspects of this transition, and different aspects of these studies can be understood in both physical pictures. There are still fundamental questions which have not been answered. (1) What is the role of the spin-orbit interaction (SOC) for the volume-collapse? (2) What is the ...

show abstract

“…17,18 According to the modern descriptions not the occupancy of the f electrons but its spectral weight shifts as the temperature is raised due to the unlocking of the Kondo state. 19 The most important fact is, however, that the volume collapse transition is accompanied by electron delocalization, as one would intuitively expect. The delocalization manifests itself by an increase in double occupancies of the d orbitals.…”

Section: Theorymentioning

confidence: 98%

Photoinduced ultrafast local volume changes in intermediate-valence solids

Diakhate

Garcia

2009

Phys. Rev. B

View full text Add to dashboard Cite

We present a theoretical model for the description of the ultrafast structural response of intermediate-valence solids to femtosecond laser excitation. The approach includes the calculation of the free energy of the hot electrons produced by the laser pulse and the determination of the changes in the thermodynamic and elastic properties of the solid as a consequence of the excitation. In particular and based on the promotional RamirezFalicov model, we consider the femtosecond laser heating of ␣ cerium and the subsequent ultrafast lattice expansion dynamics. For this purpose, we determine the thermodynamic properties of cerium at very high electronic temperatures ͑simulating the laser excitation͒. The possibility for a nonequilibrium photoinduced inverse volume collapse transition is discussed. We consider both the laser-excited and the unexcited parts of the system in order to account for inertial confinement. The thermodynamic properties are obtained as function of time and used to calculate the shock velocity variation and the time scale for expansion of the heated spot into the surrounding ͑unheated͒ part of the sample. A transition on a subpicosecond time scale is predicted.

show abstract

Theα→γTransition in Ce: A Theoretical View from Optical Spectroscopy

Cited by 123 publications

References 25 publications

Screening of4fmoments and delocalization in the compressed light rare earths

Screening of4fmoments and delocalization in the compressed light rare earths

γ−αIsostructural Transition in Cerium

Photoinduced ultrafast local volume changes in intermediate-valence solids

Contact Info

Product

Resources

About