Pressure-Induced Valence Transitions in Rare Earth Chalcogenides and Pnictides

Svane, A.; Strange, Paul; Temmerman, W. M.; Szotek, Z.; Winter, H.; Petit, L.

doi:10.1002/1521-3951(200101)223:1<105::aid-pssb105>3.0.co;2-i

Cited by 47 publications

(26 citation statements)

References 58 publications

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“…SIC-LSD calculations in Yb compounds (Svane et al, 2001(Svane et al, , 2000 predict that YbS is strongly divalent (n eff = 2 at T =0 K), as the trivalent excited state is located far above in energy. On the other hand, YbAl 2 is supposed to be weakly trivalent (n eff = 2.46).…”

Section: Ybs and Ybalmentioning

confidence: 99%

Inelastic x-ray scattering by electronic excitations under high pressure

Rueff¹,

Shukla²

2010

Rev. Mod. Phys.

176

140

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Investigating electronic structure and excitations under extreme conditions gives access to a rich variety of phenomena. High pressure typically induces behavior such as magnetic collapse and the insulator-metal transition in 3d transition metals compounds, valence fluctuations or Kondo-like characteristics in f -electron systems, and coordination and bonding changes in molecular solids and glasses. This article reviews research concerning electronic excitations in materials under extreme conditions using inelastic x-ray scattering (IXS). IXS is a spectroscopic probe of choice for this study because of its chemical and orbital selectivity and the richness of information it provides. Being an all-photon technique, IXS has a penetration depth compatible with high pressure requirements. Electronic transitions under pressure in 3d transition metals compounds and f -electron systems, most of them strongly correlated, are reviewed. Implications for geophysics are mentioned. Since the incident X-ray energy can easily be tuned to absorption edges, resonant IXS, often employed, is discussed at length. Finally studies involving local structure changes and electronic transitions under pressure in materials containing light elements are briefly reviewed.

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Section: Ybs and Ybalmentioning

confidence: 99%

Inelastic x-ray scattering by electronic excitations under high pressure

Rueff¹,

Shukla²

2010

Rev. Mod. Phys.

176

140

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“…They have been reported for a few elements, such as Ce (a well-known example of the isostructural transition), 40 Zr, 41 Os, 42 and recently B. 43 In some cases, the isostructural phase transition is related to compounds containing elements with a variable chemical valence due to fully or partially free dand/or f -electronic shells (for example, SmS, 44 EuCo 2 P 2 , 45 rare-earth chalcogenides 46 and pnictides, 47 [53][54][55] where a pressure-induced isostructural phase transition seems to be related to an electronic topological transition driven by the distortion of the electronic band structure near the Fermi surface resulting in a topological van Hove singularity crossing the Fermi level. Similarly, recent theoretical calculations predict a first-order isostructural transformation in PdN 2 driven by a phase transition of the electronic structure, which is manifested by a discontinuous change in the hybridization between Pd d and N p electrons as well as a conversion from single to triple bonded nitrogen dimmers.…”

Section: Structural and Electronic Changes Under Pressurementioning

confidence: 99%

Structural and vibrational study of cubic Sb2O3under high pressure

et al. 2012

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We report an experimental and theoretical study of antimony oxide (Sb 2 O 3 ) in its cubic phase (senarmontite) under high pressure. X-ray diffraction and Raman scattering measurements up to 18 and 25 GPa, respectively, have been complemented with ab initio total-energy and lattice-dynamics calculations. X-ray diffraction measurements do not provide evidence of a space-group symmetry change in senarmontite up to 18 GPa. However, Raman scattering measurements evidence changes in the pressure coefficients of the Raman mode frequencies at 3.5 and 10 GPa, respectively. The behavior of the Raman modes with increasing pressure up to 25 GPa is fully reproduced by the lattice-dynamics calculations in cubic Sb 2 O 3 . Therefore, the combined analysis of both experiments and lattice-dynamics calculations suggest the occurrence of two isostructural phase transformations at 3.5 and 10 GPa, respectively. Total-energy calculations show that the isostructural phase transformations occur through local atomic displacements in which senarmontite loses its molecular character to become a three-dimensional solid. In addition, our calculations provide evidence that cubic senarmontite cannot undergo a phase transition to orthorhombic valentinite at high pressure, and that a phase transition to a β-Bi 2 O 3 -type structure is possible above 25 GPa.

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“…However due to the LMTO-ASA approximations, significant uncertainty persists in the values of the total energy differences between different crystal structures. Also the spin-orbit interaction can significantly alter the results: we found that without spin-orbit the structural transition occurs at 137 kbar 19 , however without an isostructural transition occurring first. Fig.…”

mentioning

confidence: 99%

Pressure induced valence transitions inf-electron systems

et al. 2007

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A review is given of pressure induced valence transitions in f -electron systems calculated with the self-interaction corrected local spin density (SIC-LSD) approximation. These calculations show that the SIC-LSD is able to describe valence changes as a function of pressure or chemical composition. An important finding is the dual character of the f -electrons as either localized or band-like. A finite temperature generalisation is presented and applied to the study of the p-T phase diagram of the α → γ phase transition in Ce.

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Pressure-Induced Valence Transitions in Rare Earth Chalcogenides and Pnictides

Cited by 47 publications

References 58 publications

Inelastic x-ray scattering by electronic excitations under high pressure

Inelastic x-ray scattering by electronic excitations under high pressure

Structural and vibrational study of cubic Sb2O3under high pressure

Pressure induced valence transitions inf-electron systems

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