arXiv subjects

Dmitry Reznik

Publications and source records attributed to Dmitry Reznik.

20 records · Page 2Linked to original sources

arXiv2015

High-energy electronic excitations in Sr$_2$IrO$_4$ observed by Raman scattering

Spin-orbit interaction in Sr$_2$IrO$_4$ leads to the realization of the $J_{\mathrm{eff}}$ = 1/2 state and also induces an insulating behavior. Using large-shift Raman spectroscopy, we found two high-energy excitations of the d-shell multipletat at 690 meV and 680 meV with $A_{1g}$ and $B_{1g}$ symmetry respectively. As temperature decreases, the $A_{1g}$ and $B_{1g}$ peaks narrow, and the $A_{1g}$ peak shifts to higher energy while the energy of the $B_{1g}$ peak remains the same. When 25$\%$ of Ir is substituted with Rh the $A_{1g}$ peak softens by 10$\%$ but the $B_{1g}$ peak does not. We show that both pseudospin-flip and non-pseudosin-flip dd electronic transitions are Raman active, but only the latter are observed.

cond-mat.str-el↗

arXiv2014

Spurious peaks arising from multiple scattering events involving cryostat walls in inelastic neutron scattering

Well defined peaks with energies of about 18 meV have been observed in a variety of inelastic neutron scattering experiments on single crystals as well as on powders of iron-based superconductors and their parent compounds using either the triple-axis or the time-of-flight technique. They can easily be mistaken for signatures of real excitations. We have found that they are due to multiple scattering events involving primarily walls of the sample environment. Hence, they are particularly troublesome in experiments using very small samples as have been used with recently developed high intensity neutron spectrometers. It will be discussed what needs to be done to reduce the unwanted scattering to a minimum.

cond-mat.mtrl-sci↗