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High-harmonic generation in quantum spin systems

Takayoshi, Shintaro ; Murakami, Yuta ; Werner, Philipp

In: Physical Review B, 2019, vol. 99, no. 18, p. 184303

We theoretically study the high-harmonic generation (HHG) in one-dimensional spin systems. While in electronic systems the driving by ac electric fields produces radiation from the dynamics of excited charges, we consider here the situation where spin systems excited by a magnetic field pulse generate radiation via a time- dependent magnetization. Specifically, we study the magnetic dipole...

Scaling of the Fano effect of the in-plane Fe-As phonon and the superconducting critical temperature in ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{K}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$

Xu, Bing ; Cappelluti, E. ; Benfatto, Larra ; Mallett, Benjamin P. P. ; Marsik, Premysl ; Sheveleva, Evgeniia ; Lyzwa, Fryderyk ; Wolf, Thomas ; Yang, Rui ; Qiu, X. G. ; Dai, Y. M. ; Wen, H. H. ; Lobo, R. P. S. M. ; Bernhard, Christian

In: Physical Review Letters, 2019, vol. 122, no. 21, p. 217002

By means of infrared spectroscopy, we determine the temperature-doping phase diagram of the Fano effect for the in-plane Fe-As stretching mode in Ba1−xKxFe2As2. The Fano parameter 1=q2, which is a measure of the phonon coupling to the electronic particle-hole continuum, shows a remarkable sensitivity to the magnetic and structural orderings at low temperatures. Most strikingly, at elevated...

The Unique Properties of Superconductivity in Cuprates

Müller, K.

In: Journal of Superconductivity and Novel Magnetism, 2014, vol. 27, no. 10, p. 2163-2179

Band-selective clean-limit and dirty-limit superconductivity with nodeless gaps in the bilayer iron-based superconductor ${\mathrm{CsCa}}_{2}{\mathrm{Fe}}_{4}{\mathrm{As}}_{4}{\mathrm{F}}_{2}$

Xu, Bing ; Wang, Z. C. ; Sheveleva, Evgeniia ; Lyzwa, Fryderyk ; Marsik, Premysl ; Cao, G. H. ; Bernhard, Christian

In: Physical Review B, 2019, vol. 99, no. 12, p. 125119

Spin-freezing and the Sachdev-Ye model

Werner, Philipp ; Kim, Aaram J. ; Hoshino, Shintaro

In: EPL (Europhysics Letters), 2018, vol. 124, no. 5, p. 57002

Spin-freezing is the origin of bad-metal physics and non-Fermi liquid (non-FL) properties in a broad range of correlated compounds. In a multi-orbital lattice system with Hund coupling, doping of the half-filled Mott insulator results in a highly incoherent metal with frozen magnetic moments. These moments fluctuate and collapse in a crossover region that is characterized by unusual non-Fermi...

Coupled Cu and Mn charge and orbital orders in YBa₂Cu₃O₇/Nd 0.65 (Ca 1-y Sr y ) 0.35 MnO₃ multilayers

Perret, Edith ; Monney, Claude ; Johnston, S. ; Khmaladze, Jarji ; Lyzwa, Fryderyk ; Gaina, Roxana ; Dantz, M. ; Pelliciari, Jonathan ; Piamonteze, C. ; Mallett, B.P.P. ; Minola, M. ; Keimer, B. ; Schmitt, Thorsten ; Bernhard, Christian

In: Communications Physics, 2018, vol. 1, no. 1, p. 45

The observation of a charge density wave in the underdoped cuprate high Tc superconductors (Cu-CDW) raised a debate about its relationship with superconductivity. In bulk YBa2Cu3O7−δ the Cu-CDW is incipient and mainly pinned by defects. Nevertheless, a large magnetic field can induce a true long-range Cu- CDW order as it suppresses superconductivity. An enhanced Cu-CDW order was also ...

Optical study of Dirac fermions and related phonon anomalies in the antiferromagnetic compound CaFeAsF

Xu, Bing ; Xiao, H. ; Gao, B. ; Ma, Y. H. ; Mu, G. ; Marsik, Premysl ; Sheveleva, Evgeniia ; Lyzwa, Fryderyk ; Dai, Y. M. ; Lobo, R. P. S. M. ; Bernhard, Christian

In: Physical Review B, 2018, vol. 97, no. 19, p. 195110

We performed optical studies on CaFeAsF single crystals, a parent compound of the 1111-type iron-based superconductors that undergoes a structural phase transition from tetragonal to orthorhombic at Ts=121 K and a magnetic one to a spin density wave (SDW) state at TN=110 K. In the low-temperature optical conductivity spectrum, after the subtraction of a narrow Drude peak, we observe a...

Thin Film, Near-Surface and Multi-Layer Investigations by Low-Energy μ +SR

Prokscha, T. ; Morenzoni, E. ; Suter, A. ; Khasanov, R. ; Luetkens, H. ; Eshchenko, D. ; Garifianov, N. ; Forgan, E. ; Keller, H. ; Litterst, J. ; Niedermayer, C. ; Nieuwenhuys, G.

In: Hyperfine Interactions, 2004, vol. 159, no. 1-4, p. 227-234

NMR of bicelles: orientation and mosaic spread of the liquid-crystal director under sample rotation

Zandomeneghi, Giorgia ; Tomaselli, Marco ; Williamson, Philip ; Meier, Beat

In: Journal of Biomolecular NMR, 2003, vol. 25, no. 2, p. 113-123

Phenomenological theory of the s-wave state in superconductors without an inversion center

Frigeri, P. A. ; Agterberg, D. F. ; Milat, I. ; Sigrist, M.

In: The European Physical Journal B - Condensed Matter and Complex Systems, 2006, vol. 54, no. 4, p. 435-448