اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدUltrafast Quasiparticle Dynamics and Electron-Phonon Coupling in (Li0.84Fe0.16)OHFe0.98Se
108
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Distinctive superconducting behaviors between bulk and monolayer FeSe make it challenging to obtain a unified picture of all FeSe-based superconductors. We investigate the ultrafast quasiparticle (QP) dynamics of an intercalated superconductor (Li1-xFex)OHFe1-ySe, which is a bulk crystal but shares a similar electronic structure with single-layer FeSe on SrTiO3. We obtain the electron-phonon coupling (EPC) constant {lambda}A1g (0.22 +/- 0.04), which well bridges that of bulk FeSe crystal and single-layer FeSe on SrTiO3. Moreover, we find that such a positive correlation between {lambda}A1g and superconducting Tc holds among all known FeSe-based superconductors, even in line with reported FeAs-based superconductors. Our observation indicates possible universal role of EPC in the superconductivity of all known categories of iron-based superconductors, which is a critical step towards achieving a unified superconducting mechanism for all iron-based superconductors.
قيم البحث
اقرأ أيضاً
Quasiparticle dynamics of FeSe single crystals revealed by dual-color transient reflectivity measurements ({Delta}R/R) provides unprecedented information on Fe-based superconductors. The amplitude of fast component in {Delta}R/R clearly tells a compe
ting scenario between spin fluctuations and superconductivity. Together with the transport measurements, the relaxation time analysis further exhibits anomalous changes at 90 K and 230 K. The former manifests a structure phase transition as well as the associated phonon softening. The latter suggests a previously overlooked phase transition or crossover in FeSe. The electron-phonon coupling constant {lambda} is found to be 0.16, identical to the value of theoretical calculations. Such a small {lambda} demonstrates an unconventional origin of superconductivity in FeSe.
We present a combined density-functional-perturbation-theory and inelastic neutron scattering study of the lattice dynamical properties of YNi2B2C. In general, very good agreement was found between theory and experiment for both phonon energies and l
ine widths. Our analysis reveals that the strong coupling of certain low energy modes is linked to the presence of large displacements of the light atoms, i.e. B and C, which is unusual in view of the rather low phonon energies. Specific modes exhibiting a strong coupling to the electronic quasiparticles were investigated as a function of temperature. Their energies and line widths showed marked changes on cooling from room temperature to just above the superconducting transition at Tc = 15.2 K. Calculations simulating the effects of temperature allow to model the observed temperature dependence qualitatively.
Employing the momentum-sensitivity of time- and angle-resolved photoemission spectroscopy we demonstrate the analysis of ultrafast single- and many-particle dynamics in antiferromagnetic EuFe2As2. Their separation is based on a temperature-dependent
difference of photo-excited hole and electron relaxation times probing the single particle band and the spin density wave gap, respectively. Reformation of the magnetic order occurs at 800 fs, which is four times slower compared to electron-phonon equilibration due to a smaller spin-dependent relaxation phase space.
We report on Raman scattering experiments of the undoped SrFe2As2 and superconducting Sr0.85K0.15Fe2As2 (Tc=28K) and Ba0.72K0.28Fe2As2 (Tc=32K) single crystals. The frequency and linewidth of the B1g mode at 210 cm-1 exhibits an appreciable temperatu
re dependence induced by the superconducting and spin density wave transitions. We give estimates of the electron-phonon coupling related to this renormalization. In addition, we observe a pronounced quasi-elastic Raman response for the undoped compound, suggesting persisting magnetic fluctuations to low temperatures. In the superconducting state the renormalization of an electronic continuum is observed with a threshold energy of 61cm-1.
We provide a novel experimental method to quantitatively estimate the electron-phonon coupling and its momentum dependence from resonant inelastic x-ray scattering (RIXS) spectra based on the detuning of the incident photon energy away from an absorp
tion resonance. We apply it to the cuprate parent compound NdBa$_2$Cu$_3$O$_6$ and find that the electronic coupling to the oxygen half-breathing phonon mode is strongest at the Brillouin zone boundary, where it amounts to $sim 0.17$ eV, in agreement with previous studies. In principle, this method is applicable to any absorption resonance suitable for RIXS measurements and will help to define the contribution of lattice vibrations to the peculiar properties of quantum materials.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
