In: The European Physical Journal B, 2015, vol. 88, no. 3, p. 1-12
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In: Journal of Superconductivity and Novel Magnetism, 2015, vol. 28, no. 4, p. 1231-1236
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In: Physical Review B, 2020, vol. 101, no. 22, p. 224515
The magnetic and superconducting properties of a series of underdoped Ba 1 − x Na x Fe 2 As 2 (BNFA) single crystals with 0.19 ≤ x ≤ 0.34 have been investigated with the complementary muon-spin-rotation ( μ SR ) and infrared spectroscopy techniques. The focus has been on the different antiferromagnetic states in the underdoped regime and their competition with superconductivity,...
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In: Proceedings of the National Academy of Sciences, 2020, vol. 117, no. 44, p. 27104–27110
We report the optical conductivity in high-quality crystals of the chiral topological semimetal CoSi, which hosts exotic quasiparticles known as multifold fermions. We find that the optical response is separated into several distinct regions as a function of frequency, each dominated by different types of quasiparticles. The low-frequency intraband response is captured by a narrow Drude peak...
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In: Physical Review B, 2020, vol. 102, no. 16, p. 165136
We show that a metastable η-pairing superconducting phase can be induced by photodoping doublons and holes into a strongly repulsive fermionic Hubbard model. The doublon-hole condensate originates from an intrinsic doublon-hole exchange interaction and does not rely on the symmetry of the half-filled Hubbard model. It extends over a wide range of doublon densities and effective temperatures....
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In: Applied Physics Letters, 2020, vol. 117, no. 6, p. 062401
The binary compound V3Ga can exhibit two near-equilibrium phases, the A15 structure that is superconducting and the Heusler D03 structure that is semiconducting and antiferromagnetic. Density functional theory calculations show that these two phases are nearly degenerate, being separated in energy by only ±10 meV/atom. Our magnetization measurements on bulk-grown samples show ...
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In: Modern Physics Letters B, 2020, vol. 34, no. 19n20, p. 2040054
Ultrafast laser pulses can redistribute charges in Mott insulators on extremely short time scales, leading to the fast generation of photocarriers. It has recently been demonstrated that these photocarriers can form a novel η-paired condensate at low temperatures, featuring a staggered superconducting pairing field. In this conference paper, we discuss the origin of the η-paired hidden...
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In: Physical Review B, 2020, vol. 101, no. 21, p. 214512
We studied the infrared response of polycrystalline samples of the iron arsenide superconductor (Rb,Cs)Ca2Fe4As4F2 (Rb,Cs-12442), which has a bilayer structure similar to the high-Tc cuprates YBa2Cu3O7 (YBCO) and Bi2Sr2CaCu2O8. The c-axis reflectivity spectra Rc have been derived from the reflectivity spectra of the polycrystalline samples Rpoly and the in-plane spectrum of a corresponding...
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In: EPL (Europhysics Letters), 2020, vol. 129, no. 3, p. 37002
We studied how an additional layer of the high superconductor YBCO affects the magneto-transport across a LSMO/Alq3/Co spin-valve structure. We found that up to a thickness of at least 10 nm the YBCO layer on top of LSMO hardly changes the spin-valve effect, since the device resistance still depends on the relative orientation of the LSMO and Co magnetization. The spin-valve effect persists...
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In: Physical Review B, 2020, vol. 101, no. 4, p. 041104
Superconductivity with a remarkably high Tc has recently been found in Sr-doped NdNiO2 thin films. While this system bears strong similarities to the cuprates, some differences, such as a weaker antiferromagnetic exchange coupling and possible high-spin moments on the doped Ni sites have been pointed out. Here, we investigate the effect of Hund coupling and crystal field splitting in a simple...
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