Resonant Soft X-Ray Scattering from Stripe-Ordered La2−xBaxCuO4 Detected by a Transition-Edge Sensor Array Detector

Abstract

Resonant soft x-ray scattering (RSXS) is a leading probe of valence band order in materials best known for establishing the existence of charge density wave order in the copper-oxide superconductors. One of the biggest limitations on the RSXS technique is the presence of a severe fluorescence background which, like the RSXS cross section itself, is enhanced under resonance conditions. This background prevents the study of weak signals such as diffuse scattering from glassy or fluctuating order that is spread widely over momentum space. Recent advances in superconducting transition edge sensor (TES) detectors have led to major improvements in resolution and detection efficiency in the soft x-ray range. Here, we perform a RSXS study of stripe-ordered La2−xBaxCuO4 at the Cu L 3/2 edge (932.2 eV) using a TES detector with 1.5 eV resolution, to evaluate its utility for mitigating the fluorescence background problem. We find that, for suitable degree of detuning from the resonance, the TES could be used to reject the fluorescence background, leading to a 5 to 10 times improvement in the statistical quality of the data compared to an equivalent, energy-integrated measurement. We conclude that a TES presents a promising approach to reducing background in RSXS studies and may lead to new discoveries in materials exhibiting valence band order that is fluctuating or glassy.

Generic character of charge and spin density waves in superconducting cuprates

“…To exclude other factors that may affect the hole doping, we also directly measured the hole concentration from the O K edge x-ray absorption spectra (XAS) [28]. The XAS were measured in total fluorescence yield mode using a transition edge sensor (TES) array detector [29,30], which provides an excellent detection efficiency, at beamline 13-3 of the Stanford Synchrotron Radiation Lightsource (SSRL). The measured hole doping p showed a good agreement with the Sr concentration x (see SI Appendix II).…”

Generic character of charge and spin density waves in superconducting cuprates

“…To exclude other factors that may affect the hole doping, we also directly measured the hole concentration from the O K edge X-ray absorption spectra (XAS) ( 31 ). The XAS were measured in total fluorescence yield mode using a transition edge sensor (TES) array detector ( 32 , 33 ), which provides an excellent detection efficiency, at beamline 13-3 of the Stanford Synchrotron Radiation Lightsource (SSRL). The measured hole doping p showed a good agreement with the Sr concentration x ( SI Appendix , section II ).…”

Transition edge sensor based detector: from X-ray to $γ$-ray

“…In addition to the rapid analysis of general materials, there is an urgent demand for energy spectrum measurement of dim and non-point X-ray sources, so the demand for TES X-ray detectors is increasing [4][5][6]8]. TES X-ray detectors have been used in research areas such as low-Z element Xray emission spectroscopy (XES) [5], X-ray absorption nearedge spectroscopy [20][21][22], time-resolved X-ray absorption and emission spectroscopy [10][11][12], resonant soft X-ray scattering (RSXS) [23]. On particle accelerators, TES X-ray detectors have been used for meson atomic energy spectrum measurements such as π and κ [8].…”