One-component order parameter in URuSi uncovered by resonant ultrasound spectroscopy and machine learning.

The unusual correlated state that emerges in URuSi below = 17.5 K is known as "hidden order" because even basic characteristics of the order parameter, such as its dimensionality (whether it has one component or two), are "hidden." We use resonant ultrasound spectroscopy to measure the symmetry-resolved elastic anomalies across .

Author Correction: Thermodynamic Signatures of Weyl Fermions in NbP.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Spatial control of heavy-fermion superconductivity in CeIrIn.

Although crystals of strongly correlated metals exhibit a diverse set of electronic ground states, few approaches exist for spatially modulating their properties. In this study, we demonstrate disorder-free control, on the micrometer scale, over the superconducting state in samples of the heavy-fermion superconductor CeIrIn We pattern crystals by focused ion beam milling to tailor the boundary conditions for the elastic deformation upon thermal contraction during cooling. The resulting nonuniform strain fields induce complex patterns of superconductivity, owing to the strong dependence of the transition temperature on the strength and direction of strain.

Persistent antiferromagnetic order in heavily overdoped Ca La FeAs.

In the Ca La FeAs (1 1 2) family of pnictide superconductors, we have investigated a highly overdoped composition (x  =  0.56), prepared by a high-pressure, high-temperature synthesis. Magnetic measurements show an antiferromagnetic transition at T   =  120 K, well above the one at lower doping (0.

Thermodynamic Signatures of Weyl Fermions in NbP.

We present a high magnetic field study of NbP-a member of the monopnictide Weyl semimetal (WSM) family. While the monoarsenides (NbAs and TaAs) have topologically distinct left and right-handed Weyl fermi surfaces, NbP is argued to be "topologically trivial" due to the fact that all pairs of Weyl nodes are encompassed by a single Fermi surface. We use torque magnetometry to measure the magnetic response of NbP up to 60 tesla and uncover a Berry paramagnetic response, characteristic of the topological Weyl nodes, across the entire field range.