Search

Tuning the structure in the atomic scale enables manipulation of the quantum state in a molecular based system. Here, Hiraokaet al. tune the Kondo coupling between molecular spins and the Au electrode by controlling the position of Fe²⁺ions in the molecular cage with a tip.

The study and application of the conductive surface states of topological insulators are often restricted by the presence of bulk conduction states. Here, Xu et al. present evidence for such topological surface states with true bulk insulation in the strongly correlated Kondo insulator SmB₆.

The competition between interactions promoting magnetic order and those suppressing magnetism causes unusual electronic behaviour in Kondo lattice materials. Here, the authors show the energy scale for valence fluctuations is not controlled by the Kondo scale, contrary to expectations from single-site models.

The mechanism underlying screening of a Kondo lattice of magnetic moments by conduction electrons is an important unsolved problem. Figgins et al. use STM techniques to assemble nanoscale Kondo droplets that extrapolate between a single moment and the Kondo lattice, providing a platform for further study.

The Kondo effect from magnetic impurities has been proposed as a probe of fractionalized excitations in a topological quantum spin liquid. Lee et al. experimentally demonstrate the Kondo effect in a Kitaev candidate material α-RuCl3 with dilute Cr impurities.

The quantum critical behaviour of a two-impurity Kondo model variant is observed in a system of hybrid-semiconductor islands that could provide a scalable platform for solid-state quantum simulation

Reports of quantum oscillations in the absence of an electronic Fermi surface in Kondo insulator candidates such as SmB₆ and YbB₁₂ have been under intense study. Here the authors report the thermodynamic properties of YbB₁₂ in a magnetic field pointing to the presence of in-gap fermionic excitations.

The fate of high-energy degrees of freedom, such as spin-orbit interactions, in the coherent state of Kondo lattice materials remains unclear. Here, the authors use resonant inelastic x-ray scattering in CePd₃ to show how Kondo-quasiparticle excitations are renormalized and develop a pronounced momentum dependence, while maintaining a largely unchanged spin-orbit gap.

In rare-earth intermetallics, interaction between localized 4f electrons and itinerant electrons can result in exotic states of matter. Here, the authors use photoemission spectroscopy to reveal and study this interaction in the bulk and at the surface of the Kondo lattice antiferromagnet CeRh₂Si₂.

Exploring the interplay of quantum effects enriches the scientific and technological understanding in nanoscale devices. The authors find that two apparently different quantum effects, quantum interference and the Kondo effect, can be unified to describe electron transport in single-molecule junctions.

The interaction of localized and conduction electrons in some heavy fermion materials is believed to give rise to a Kondo insulating state. Kushwaha et al. present evidence that Ce3Bi4Pd3 is a Kondo insulator with a gap small enough to be driven into a Fermi liquid phase with accessible magnetic fields.

Experimental study of the Kondo insulator SmB₆ provides an alternative route to realize a Fermi surface in the absence of a conventional Fermi liquid.

Using terahertz pulses, the quasiparticle dynamics of the heavy-fermion compound CeCu_6−xAu are investigated in the vicinity of its quantum critical point.

A quantum critical point occurs when different stable phases of matter are in equilibrium at absolute zero temperature. Describing quantum criticality with a theoretical framework that unifies different types of transitions is highly desirable to understand how phenomena such as superconductivity and magnetism interact in correlated electron systems. A study now provides an indication of an underlying universality of quantum criticality, and highlights the role of dimensionality in such a unified theory.

High-energy-resolution spectroscopic measurements performed on the Kondo insulator SmB₆ reveal the presence of correlation-driven heavy surface states—the heavy Dirac fermions—and shed light on the search for the correlated topological materials.

Anisotropic hybridization between conduction and unpaired f electrons is rarely observed. Now, a lanthanide-based two-dimensional compound exhibits nodal hybridization, giving rise to heavy-fermion behaviour.

In molecular spintronics, the spin state of a molecule may be switched by changing the molecular structure. Here, the spin of a single-molecule magnet is switched by applying an electric current using a scanning tunnelling microscope, which may aid in information coding at the single-molecule level.

Manipulation of topology of the electronic structure is highly desirable for practical applications of topological materials. Here the authors demonstrate tuning and annihilation of Weyl nodes in momentum space by means of the Zeeman effect in a strongly correlated topological semimetal Ce₃Bi₄Pd₃.

The strength of the interaction between the spin state and orbital motion of electrons in a semiconducting quantum dot can be controlled by electrical gates.

We present comprehensive thermodynamic and spectroscopic evidence for an antiferromagnetically ordered heavy-fermion ground state in the van der Waals metal CeSiI.

The authors report that the metallic spin-1/2 chain compound Ti₄MnBi₂ forms near a quantum critical point with inherent frustration. They identify strong 1D spin and 3D electron coupling that should stimulate the search for materials exhibiting a 1D Kondo effect and heavy fermions.

Complex oxide devices provide a platform for studying and making use of strongly correlated electronic behavior. Here the authors present a LaAlO₃/SrTiO₃ quantum dot and show that its transport behavior is consistent with the presence of attractive electron interactions and the charge Kondo effect.

Clathrate materials have been the subject of intense investigation because of their beneficial properties, in particular their low thermal conductivities. Now, improved thermopower at high temperatures arising from strong electron correlation effects has been achieved in a type-I clathrate containing cerium guest atoms.

A tunable concentration of localized magnetic impurities is inserted into a metal from a molecular monolayer, which allows many-body phenomena in magnetic impurity–host systems to be studied at unprecedented impurity concentrations.

Charge-neutral excitations have been proposed to explain metal-like thermal transport in Kondo insulators. Here, the authors demonstrate the coupling between charge-neutral excitations and spin degrees of freedom in a Kondo insulator YbIr₃Si₇, which puts restrictions on current theories.

The interactions of quasiparticles can be described by renormalizing their masses, such that some materials have a vanishingly small effective mass, whereas others have a very high effective mass. The observation by Vyalikh and colleagues of both extremes occurring on the surface and interior of the same material offers a new view of many-body interactions.

Information technology based on few atom magnets requires both long spin-energy relaxation times and flexible inter-bit coupling. Here, the authors show routes to manipulate information in three-atom clusters strongly coupled to substrate electrons by exploiting Dzyaloshinskii–Moriya interactions.

Heavy-fermion materials have unusual electronic behavior due to a dual localized-itinerant character of 4f electrons. Here, by studying divalent EuRh₂Si₂, the authors gain insight into the electronic states of the trivalent heavy fermion system YbRh₂Si₂ and show that it experimentally demonstrates Luttinger’s theorem.

Kayama et al. present a blueprint for a national genomic surveillance study that conducts genome sequencing of thousands of strains, integrates standardized quantitative antimicrobial susceptibility testing, and characterizes antimicrobial resistance determinants.

Coupling superconductors to mesoscopic systems leads to unusual effects that could be exploited in new devices including topological quantum computers. Here the authors present a double quantum dot with a Yu–Shiba–Rusinov ground state arising from the interplay of Coulomb interactions and superconductivity.

Recently, rich condensed matter physics has emerged from the interplay between band topology and magnetic order. Here, the authors characterize the magnetic Weyl semimetal CeAlGe and find evidence for the role of Weyl fermions in stabilizing the magnetic order above the local transition temperature.

The heavy-fermion compound YbRh₂Si₂ possesses a quantum critical point, at which the standard theory of electron behaviour in metals is expected to break down; such anomalous behaviour has now been observed.

Although LaAlO₃ and SrTiO₃ are both insulators, when they are brought together at a (100) interface, a highly conducting two-dimensional electron gas forms between them. Annandi et al.show that this also happens at a (110) interface, counter to expectations that it should not.

Coherently projecting a quantum state may allow it to be probed from a distance. This is now demonstrated for a Yu–Shiba–Rusinov state using a quantum corral.

A detailed theoretical approach is used to identify the electronic mechanisms responsible for the anomalous behaviour of late actinides, and reveals that plutonium has an unusual mixed-valent ground state.

The coupling of spin and orbital motion of electrons in carbon nanotubes has been demonstrated before, but a study now shows that the strength and sign of the spin–orbit coupling can be tuned by a gate voltage, and that, importantly for future applications, the effect survives in the presence of disorder.

Despite much recent effort, the highest reported T_c of the infinite-layer nickelates remains lower than 15 K. Here, the authors apply pressure to Pr_0.82Sr_0.18NiO₂ thin films and observe a monotonic increase of T_c to 31 K at 12.1 GPa, an increase that does not level off with increasing pressure.

Samarium hexahoride is argued to be a topological Kondo insulator, but this claim remains under debate. Here, Hlawenka et al. provide a topologically trivial explanation for the conducting states at the (100) surface of samarium hexaboride; an explanation based on Rashba splitting and a surface shift of the Kondo resonance.

Thermal-expansion measurements of CeCu_6−xAu_x reveal the thermodynamic landscape of this material’s entropy, offering insights into the behaviour of quantum critical fluctuations as the system approaches its quantum critical point.

Achieving deep blue emission and high practical efficiency in organic light-emitting devices remains a considerable challenge. Here, the authors report late-stage double borylation of boron/nitrogen based multi-resonance frameworks, achieving maximum efficiency of over 32% in stable devices.