Fermi surface and kink structures in $$\hbox {Sr}_{{4}}\hbox {Ru}_{{3}}\hbox {O}_{{10}}$$ revealed by synchrotron-based ARPES

The low-energy electronic structure, including the Fermi surface topology, of the itinerant metamagnet $$\hbox {Sr}_{{4}}\hbox {Ru}_{{3}}\hbox {O}_{{10}}$$ Sr 4 Ru 3 O 10 is investigated for the first time by synchrotron-based angle-resolved photoemission. Well-defined quasiparticle band dispersions with matrix element dependencies on photon energy or photon polarization are presented. Four bands crossing the Fermi-level, giving rise to four Fermi surface sheets are resolved; and their complete topography, effective mass as well as their electron and hole character are determined. These data reveal the presence of kink structures in the near-Fermi-level band dispersion, with energies ranging from 30 to 69 meV. Together with previously reported Raman spectroscopy and lattice dynamic calculation studies, the data suggest that these kinks originate from strong electron–phonon coupling present in $$\hbox {Sr}_{{4}}\hbox {Ru}_{{3}}\hbox {O}_{{10}}$$ Sr 4 Ru 3 O 10 . Considering that the kink structures of $$\hbox {Sr}_{{4}}\hbox {Ru}_{{3}}\hbox {O}_{{10}}$$ Sr 4 Ru 3 O 10 are similar to those of the other three members of the Ruddlesden Popper structured ruthenates, the possible universality of strong coupling of electrons to oxygen-related phonons in $$\hbox {Sr}_{n+1}\hbox {Ru}_{{n}}\hbox {O}_{3n+1}$$ Sr n + 1 Ru n O 3 n + 1 compounds is proposed.

Strain-dependent structure and Raman behaviours in the heavy-ion irradiated manganite at extreme low dose

The microstrains in heavy-ion irradiated manganite LaMnO3 can be managed in linear response of irradiation dose, and the corresponding internal pressure up to 8 GPa can be induced by varying doses. The response of structure under stress is studied by means of Density Functional Theory and Lattice Dynamic Calculation. All obtained Raman scattering lines are discussed in details to shed light onto structural changes during ion implantation. There appears new resonance peak at around 550 cm−1, which splits from broad features in the spectra, and attributes to the anti-symmetric vibrations of O6 cages. The blue shift of this peak scales to ~2.4 cm−1 per 1 GPa of stress. Another strong feature showing considerable blue shift is seen in the vicinity of 640 cm−1 and corresponds to one of rhombohedral distortion related soft modes. A weak mode, not frequently reported, is seen at around 420 cm−1 and corresponds to translation-like motions of fixed O6 cages.