Andreas Baum
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View article: Numerical and experimental examination of performance curve instabilities of a centrifugal fan
Numerical and experimental examination of performance curve instabilities of a centrifugal fan Open
This paper investigates the performance curve instability of centrifugal fans used in industrial applications such as sintering or pelletizing plants. The study focuses on experimental and numerical analyses of the fan’s performance curve …
View article: Chiral electronic excitations and strong electron-phonon coupling to Weyl fermions in the Kagome semimetal Co$_3$Sn$_2$S$_2$
Chiral electronic excitations and strong electron-phonon coupling to Weyl fermions in the Kagome semimetal Co$_3$Sn$_2$S$_2$ Open
We present results of a Raman scattering study of the Kagome ferromagnet Co$_3$Sn$_2$S$_2$, with a focus on electronic and phononic excitations and their interplay. We provide a theoretical analysis of the electronic band structure, enabli…
View article: Suppression of Superconductivity and Nematic Order in Fe<sub>1–<i>y</i></sub>Se<sub>1–<i>x</i></sub>S<sub><i>x</i></sub> (0 ≤ <i>x</i> ≤ 1; <i>y</i> ≤ 0.1) Crystals by Anion Height Disorder
Suppression of Superconductivity and Nematic Order in Fe<sub>1–<i>y</i></sub>Se<sub>1–<i>x</i></sub>S<sub><i>x</i></sub> (0 ≤ <i>x</i> ≤ 1; <i>y</i> ≤ 0.1) Crystals by Anion Height Disorder Open
Connections between crystal chemistry and critical temperature Tc have been in the focus of superconductivity, one of the most widely studied phenomena in physics, chemistry, and materials science alike. In most Fe-based superconductors, m…
View article: Compressing CNN Kernels for Videos Using Tucker Decompositions: Towards Lightweight CNN Applications
Compressing CNN Kernels for Videos Using Tucker Decompositions: Towards Lightweight CNN Applications Open
Convolutional Neural Networks (CNN) are the state-of-the-art in the field of visual computing. However, a major problem with CNNs is the large number of floating point operations (FLOPs) required to perform convolutions for large inputs. W…
View article: Enhanced A1g Raman response in cuprates due to Higgs oscillations
Enhanced A1g Raman response in cuprates due to Higgs oscillations Open
In superconductors the Anderson-Higgs mechanism allows for the existence of a collective amplitude (Higgs) mode which can couple to light only in a non-linear Raman-like process. While the observed properties of the Higgs mode in conventio…
View article: Calculation of an enhanced A1g symmetry mode induced by Higgs oscillations in the Raman spectrum of high-temperature cuprate superconductors
Calculation of an enhanced A1g symmetry mode induced by Higgs oscillations in the Raman spectrum of high-temperature cuprate superconductors Open
In superconductors the Anderson-Higgs mechanism allows for the existence of a collective amplitude (Higgs) mode which can couple to eV-light mainly in a non-linear Raman-like process. The experimental non-equilibrium results on isotropic s…
View article: Raman Study of Cooper Pairing Instabilities in (Li$_{1-x}$Fe$_x$)OHFeSe
Raman Study of Cooper Pairing Instabilities in (Li$_{1-x}$Fe$_x$)OHFeSe Open
We studied the electronic Raman spectra of (Li$_{1-x}$Fe$_x$)OHFeSe as a function of light polarization and temperature. In the B$_{1g}$ spectra alone we observe the redistribution of spectral weight expected for a superconductor and two w…
View article: Frustrated magnetism from local moments in FeSe
Frustrated magnetism from local moments in FeSe Open
We investigate properties of a spin-1 Heisenberg model with extended and\nbiquadratic interactions, which captures crucial aspects of the low energy\nphysics in FeSe. While we show that the model exhibits a rich phase diagram\nwith four di…
View article: Frustrated spin order and stripe fluctuations in FeSe
Frustrated spin order and stripe fluctuations in FeSe Open
The charge and spin dynamics of the structurally simplest iron-based superconductor, FeSe, may hold the key to understanding the physics of high temperature superconductors in general. Unlike the iron pnictides, FeSe lacks long range magne…
View article: Phonon anomalies in FeS
Phonon anomalies in FeS Open
Here, we present results from light scattering experiments on tetragonal FeS with the focus placed on lattice dynamics. We identify the Raman active A1g and B1g phonon modes, a second order scattering process involving two acoustic phonons…
View article: Magnetic excitations and amplitude fluctuations in insulating cuprates
Magnetic excitations and amplitude fluctuations in insulating cuprates Open
We present results from light scattering experiments on three insulating antiferromagnetic cuprates, YBa$_2$Cu$_3$O$_{6.05}$, Bi$_2$Sr$_2$YCu$_2$O$_{8+\delta}$, and La$_2$CuO$_4$ as a function of polarization and excitation energy {using s…
View article: Interrelation of lattice, charge, and spin degrees of freedom in iron based systems
Interrelation of lattice, charge, and spin degrees of freedom in iron based systems Open
Magnetic order is a dominating phase in iron based pnictides and chalcogenides. Neither its origin nor its interplay with the neighbouring phases of nematic order and unconventional superconductivity are well understood yet. Raman spectros…
View article: Microscopic pairing fingerprint of the iron-based superconductor ${\rm Ba_{1-x}K_xFe_2As_2}$
Microscopic pairing fingerprint of the iron-based superconductor ${\rm Ba_{1-x}K_xFe_2As_2}$ Open
Resolving the microscopic pairing mechanism and its experimental identification in unconventional superconductors is among the most vexing problems of contemporary condensed matter physics. We show that Raman spectroscopy provides an avenu…
View article: Superconductivity and fluctuations in Ba<sub>1–<i>p</i></sub>K<sub><i>p</i></sub>Fe<sub>2</sub>As<sub>2</sub> and Ba(Fe<sub>1–<i>n</i></sub>Co<sub><i>n</i></sub>)<sub>2</sub>As<sub>2</sub>
Superconductivity and fluctuations in Ba<sub>1–<i>p</i></sub>K<sub><i>p</i></sub>Fe<sub>2</sub>As<sub>2</sub> and Ba(Fe<sub>1–<i>n</i></sub>Co<sub><i>n</i></sub>)<sub>2</sub>As<sub>2</sub> Open
We study the interplay of fluctuations and superconductivity in BaFe 2 As 2 (Ba‐122) compounds with Ba and Fe substituted by K (p doping) and Co (n doping), respectively. To this end, we measured electronic Raman spectra as a function of p…