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The interplay between heavy fermion systems and geometric flat bands is often hindered by a scarcity of material realizations. Here, the authors report on the coexistence of geometrically frustrated flat bands and Kondo resonance states near the Fermi level in YbCr₆Ge₆.

The phase diagram of 5% Hg-doped CeRhIn₅ reveals two distinct antiferromagnetic ground states without superconductivity, contrasting sharply with electron- and dilute hole-doped systems. This behavior highlights a fundamental asymmetry in local electronic structure: electron substitution induces homogeneous effects, whereas hole doping nucleates localized magnetic droplets. In the heavy hole-doping limit, these droplets grow to stabilize a new magnetic order and create a spatially heterogeneous electronic state. Consequently, the high impurity density locally freezes magnetic fluctuations, suppressing the canonical quantum critical signatures and preventing the formation of superconductivity near the quantum critical point.

The heavy fermion system CeRhIn₅has a local quantum critical point, but its role in the onset of superconductivity is unclear. Here, the authors tune the quantum critical point by tin doping and verify that fluctuations from the antiferromagnetic criticality promote this unconventional superconductivity.

The significance of our results is related to “the quantum breakdown of superconductivity (QBS) and the role of superconducting islands in disordered superconducting systems”. Study on the QBS uses a reverse, comprehensive approach to the appearance of superconductivity, which is of utmost importance not only to understanding the superconducting phase but also to practical applications of superconductors. However, the mechanism underlying the transition to the nonzero resistive state deep in the superconducting state is still under debate. In this work, we have successfully achieved the field-induced QBS in disordred MgB₂ thin films via a unique technique of low-energy ion irradiation.

Knowledge of critical current may provide important information to understand unconventional superconductivity and quantum critical behavior. Here, Jung et al. observe a peak in the pressure dependence of the zero-field critical current at a hidden quantum critical point in pure and Sn-doped heavy fermion superconductor CeRhIn₅.

Superconducting (SC) gap of elemental yttrium under extreme pressure conditions was directly probed via the point-contact spectroscopy (PCS) in a diamond anvil cell. Strong enhancement in the differential conductance near the zero-biased voltage is observed owing to Andreev reflection, a hallmark of superconductivity. Taken together with the large initial slope of the upper critical field, the large SC gap-to-T_c ratio suggests that Y belongs to a family of the strongly coupled BCS superconductors.

Large inhomogeneous electronic states in rare-earth-doped CaFe₂As₂ produce striking results of manipulating the superconducting phases via current-driven magnetic state. Magnetization hysteresis loops at superconducting state (2 K) and normal state (50 K) for La-doped CaFe₂As₂ are largely changed by the electric current because their high-T_c regions are localized. Current path between high-T_c regions is considered as a long wire, thus current-induced large magnetic field around the path can modulate the magnetic state in normal/weak superconducting regions. These observations provide new insights into the role of Fe in the Fe-based superconductors and ideas for the design of new superconducting devices.

Heavy-fermion superconductors feature a magnetic quantum critical point linked to the Kondo effect breakdown. Wang et al. use pressure-dependent Hall measurements to identify a crossover energy scale, confirming this in pure CeRhIn₅, while revealing a shift to spin density wave criticality with Sn-doping.

Chemical substitution often mimics the effects of applied pressure on a compound, and ‘doping’ is a standard way to reach a quantum critical point from a given phase. However, CeCoIn₅ is a natural quantum critical superconductor, and Cd-doping tunes the system away from criticality. Applied pressure reverses the effect of doping, but although superconductivity is restored, quantum criticality is not.

Ordered corundum oxides offer promising alternatives to traditional perovskites in functional oxide thin films. Here, the authors utilize layer-by-layer growth to fabricate CrVO3 superlattice thin films, achieving atomic-scale precision and stabilizing the ilmenite phase, potentially expanding the range of customizable rhombohedral oxides with unique properties.

Observations of six transiting planets around the bright nearby star HD 110067 show that they follow a chain of resonant orbits, with three of the planets inferring the presence of large hydrogen-dominated atmospheres.

Thin-film high-entropy alloy (HEA) superconductors have recently attracted a lot of attention, but their critical current density and potential usefulness in engineering applications has remained unclear. Here, the authors fabricate HEA films with remarkably high critical current density and resistance to radiation damage.

Exploring the magnetism in the van der Waals materials facilitates two dimensional spintronic devices. Here the authors demonstrate the evolution of magnetic behavior, strong perpendicular magnetic anisotropy and existence of magnetic coupling between atomic layers in Fe₃GeTe₂ nanoflakes by varying the layer thickness.

In most superconductors, the pairing-up of electrons responsible for resistance-less conduction is driven by vibrations of the solid's crystal lattice. But other materials exist in which the attractive interaction responsible for binding electrons is believed to have a very different origin: quantum fluctuations of spin or charge. This paper identifies an unusually 'violent' generalization of such pairing mechanisms, in which these spin and charge instabilities combine forces.

Three-dimensional nanocup Bi_3.25La_0.75Ti₃O₁₂–CoFe₂O₄ heterostructure film is obtained via a heavily Co, Fe co-doped ferroelectric Bi_3.25La_0.75Ti₃O₁₂ target during pulsed laser deposition. The unique 3D nanocup architecture beyond usual architectures enables reversible magnetoelectric switching of the multiferroic heterostructure film through overcoming leakage issues, as well as efficient interfacial strain coupling based on their structural benefits.

To enhance supercurrent of iron-chalcogenide (FST) superconductor thin films, we induced nanostrain in FST thin films. The nanostrain was generated around nanoscale defects which were formed by the inserted a trace amount of oxide artificially inside FST matrix during the growth of FST thin film using sequential pulsed laser deposition. In particular, the critical current density (J_c) of the nanostrained FST thin films was significantly improved without dominant degradation of critical transition temperature.