scholarly journals Soft X-Ray Spectroscopy of Low-Valence Nickelates

2021 ◽  
Vol 9 ◽  
Author(s):  
Matthias Hepting ◽  
Mark P. M. Dean ◽  
Wei-Sheng Lee
Keyword(s):  
Electronic Structure ◽  
High Temperature ◽  
High Temperature Superconductivity ◽  
Essential Elements ◽  
X Ray ◽  
Infinite Layer ◽  
X Ray Scattering ◽  
The Subject ◽  
X Ray Absorption ◽  
Degree Of Similarity

Low-valence nickelates—including infinite-layer (IL) and trilayer (TL) compounds—are longstanding candidates for mimicking the high-temperature superconductivity of cuprates. A recent breakthrough in the field came with the discovery of superconductivity in hole-doped IL nickelates. Yet, the degree of similarity between low-valence nickelates and cuprates is the subject of a profound debate for which soft x-ray spectroscopy experiments at the Ni L- and O K-edge provided critical input. In this review, we will discuss the essential elements of the electronic structure of low-valance nickelates revealed by x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS). Furthermore, we will review magnetic excitations observed in the RIXS spectra of IL and TL nickelates, which exhibit characteristics that are partly reminiscent of those of cuprates.

Enhanced insulating behavior in the Ir-vacant Sr2Ir1–x O4 system dominated by the local structure distortion

2018 ◽  
Vol 25 (4) ◽  
pp. 1123-1128 ◽  
Author(s):  
Jie Cheng ◽  
Peng Dong ◽  
Bin Li ◽  
Shengli Liu ◽  
Xiangfu Wang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
High Temperature ◽  
Atomic Structure ◽  
Local Structure ◽  
Bond Angle ◽  
Theoretical Calculations ◽  
Unconventional Superconductor ◽  
Microscopic Mechanism ◽  
X Ray ◽  
X Ray Absorption

Sr2IrO4, known as the J eff = 1/2 Mott insulator, was predicted to be an unconventional superconductor upon doping since it highly resembles the high-temperature cuprates. However, recent work pointed out an enhanced insulating behavior in the Ir-vacant Sr2Ir1–x O4 system. In this contribution, to investigate the microscopic mechanism of its enhanced insulating behavior, X-ray absorption spectroscopy was applied to study the electronic structure and local structure distortion of Sr2Ir1–x O4. Due to the presence of Ir5+ ions, the preconceived holes are barely doped in the Ir-vacant system. Nevertheless, Ir vacancies finely modulate the local atomic structure, i.e. the topology of IrO6 octahedra and the in-plane Ir—O1—Ir bond angle. Combined with theoretical calculations, it is demonstrated that both the more distorted IrO6 octahedra and decreased Ir—O1—Ir angle contribute to the increment of the band gap, and then result in the enhanced insulating state for Sr2Ir1–x O4.

Electronic Structure and X-ray Absorption Spectra of Rutile TiO2 Using First-Principles Calculations

2014 ◽  
Vol 52 (12) ◽  
pp. 1025-1029
Author(s):  
Min-Wook Oh ◽  
Tae-Gu Kang ◽  
Byungki Ryu ◽  
Ji Eun Lee ◽  
Sung-Jae Joo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Absorption Spectra ◽  
First Principles ◽  
First Principles Calculations ◽  
Rutile Tio2 ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Effect of 3d/4p Mixing on 1s2p Resonant Inelastic X-ray Scattering: Electronic Structure of Oxo-Bridged Iron Dimers

2021 ◽  
Vol 143 (12) ◽  
pp. 4569-4584
Author(s):  
Thomas Kroll ◽  
Michael L. Baker ◽  
Samuel A. Wilson ◽  
Marcus Lundberg ◽  
Amélie Juhin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Vibrational resonant inelastic X-ray scattering in liquid acetic acid: a ruler for molecular chain lengths

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Viktoriia Savchenko ◽  
Iulia Emilia Brumboiu ◽  
Victor Kimberg ◽  
Michael Odelius ◽  
Pavel Krasnov ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Acetic Acid ◽  
Molecular Chain ◽  
X Ray ◽  
X Ray Scattering ◽  
Localized Excitations ◽  
Vibrational Excitations ◽  
Chain Lengths ◽  
X Ray Absorption ◽  
Ray Scattering

AbstractQuenching of vibrational excitations in resonant inelastic X-ray scattering (RIXS) spectra of liquid acetic acid is observed. At the oxygen core resonance associated with localized excitations at the O–H bond, the spectra lack the typical progression of vibrational excitations observed in RIXS spectra of comparable systems. We interpret this phenomenon as due to strong rehybridization of the unoccupied molecular orbitals as a result of hydrogen bonding, which however cannot be observed in x-ray absorption but only by means of RIXS. This allows us to address the molecular structure of the liquid, and to determine a lower limit for the average molecular chain length.

scholarly journals Crystalline and magnetic structure of Ba2CuO3+δ investigated by x-ray absorption spectroscopy and resonant inelastic x-ray scattering

2020 ◽  
pp. 1353810
Author(s):  
Roberto Fumagalli ◽  
Abhishek Nag ◽  
Stefano Agrestini ◽  
Mirian Garcia-Fernandez ◽  
Andrew C. Walters ◽  
...  
Keyword(s):  
Magnetic Structure ◽  
Absorption Spectroscopy ◽  
X Ray ◽  
X Ray Scattering ◽  
X Ray Absorption ◽  
Ray Scattering
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