SIMES Seminar: Dr. Matteo Rossi

Date(s) - Mar 1 2019
10:00 AM - 11:00 AM

Shasta Room, Bldg. 40, Room 361


Resonant inelastic x-ray scattering studies of transition metal oxides

Matteo Rossi

Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy


Transition metal oxides of the 3d series host many fascinating physical properties. One of the most prominent phenomena is high critical temperature superconductivity in copper oxides (cuprates) [1]. In the last decade, the attention of the scientific community has extended also towards 4d and 5d transition metal oxides in view of the novel quantum phases of matter that may arise from the interplay of electron correlation and spin-orbit interaction of comparable strength [2].

Resonant inelastic x-ray scattering (RIXS) contributed enormously to our understanding of the electronic, magnetic and lattice dynamics of 3d and 5d transition metal oxides. In this talk, I will show examples of RIXS applications to the cuprate parent compound NdBa2Cu3O6 and the iridate CaIrO3.

In NdBa2Cu3O6, high-energy-resolution soft-x-ray RIXS provides unique information on the electron-phonon coupling strength and on its momentum dependence. This argument is lively discussed as the mechanism that couples electrons into bosonic Cooper pairs in unconventional superconductors is subtle and not yet understood [1]. It is argued that lattice vibrations may act in synergy with a dominant mechanism and enhance the critical temperature [3]. This work paves the way for an experimental and theoretical campaign that will establish the influence of lattice excitations on the properties of quantum materials.

CaIrO3 is peculiar among iridates, as it is the only compound where iridium ions are connected in a two-dimensional network by both corner- and edge-sharing octahedra. Despite the two-dimensional crystal structure, I will reveal that the magnetic dynamics is mainly one-dimensional. Indeed, the magnetic excitation spectrum measured by hard-x-ray RIXS displays clear similarities to the one of one-dimensional antiferromagnetic chains.



[1] B. Keimer et al. Nature 518, 179 (2015).

[2] W. Witczak-Krempa et al. Annual Review of Condensed Matter Physics 5, 57 (2014).

[3] S. Johnston et al. Phys. Rev. B 82, 064513 (2010).