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This page lists some of our favourite recent publications that we were a part of.

Abstract: The interplay of different emergent phenomena — superconductivity (SC) and domain formation — appearing on different spatial and energy scales are investigated using high-resolution scanning tunneling spectroscopy (STS) in the prototypical transition metal dichalcogenide superconductor 1T-TaSSe single crystals (TSC = 3.2 K) at temperatures from 1 to 20 K. Our major observation is that while the SC gap size smoothly varies on the scale of 10 nm, its spatial distribution is not correlated to the domain structure. On the other hand, there is statistically significant correlation of the SC gap ΔSC with spectral weight of the narrow band at the Fermi level formed from the same Ta 5d orbitals as the Mott-Hubbard band. We show that the narrow band follows the evolution of Hubbard bands in space, proving unambiguously its relation to the charge order. The correlations between the two suggest a non-trivial link between rapidly spatially varying charge order and superconductivity common in many quantum materials, and high-temperature superconductors in particular.

Abstract: In an attempt to incorporate tin (Sn) into high-entropy alloys composed of refractory metals Hf, Nb, Ti and Zr with the addition of 3d transition metals Cu, Fe, and Ni, we synthesized a series of alloys in the system HfTiZrSnM (M = Cu, Fe, Nb, Ni). The alloys were characterized crystallographically, microstructurally, and compositionally, and their physical properties were determined, with the emphasis on superconductivity. All Sn-containing alloys are multi-phase mixtures of intermetallic compounds (in most cases four). A common feature of the alloys is a microstructure of large crystalline grains of a hexagonal (Hf, Ti, Zr)5Sn3 partially ordered phase embedded in a matrix that also contains many small inclusions. In the HfTiZrSnCu alloy, some Cu is also incorporated into the grains. Based on the electrical resistivity, specific heat, and magnetization measurements, a superconducting (SC) state was observed in the HfTiZr, HfTiZrSn, HfTiZrSnNi, and HfTiZrSnNb alloys. The HfTiZrSnFe alloy shows a partial SC transition, whereas the HfTiZrSnCu alloy is non-superconducting. All SC alloys are type II superconductors and belong to the Anderson class of “dirty” superconductors.

Abstract: We report on high temperature (T) studies of conductivity, σ, of the monoclinic phase of NbS3 (NbS3-II). The compound is shown to be stable up to T∼550 K. Threshold non-linear conductivity and Shapiro steps on the I – V curves can be seen up to TP0 ≈ 450 – 475 K clearly demonstrating sliding of a charge-density wave (CDW). The feature in σ(T) shows that TP0 is the temperature of the formation of this CDW. The charges condensed in this CDW show relatively high density and, at the same time, extremely low mobility. Their mobility appears low in the single-particle states as well, giving a plausible clue to the surprising dielectric-like temperature variation of σ above TP0.