One of the main developments in unconventional superconductivity in the past two decades has been the discovery that most unconventional superconductors form phase diagrams that also contain other strongly correlated states. Many systems of interest are therefore close to more than one instability, and tuning between the resultant ordered phases is the subject of intense research1.

We measure the full elastic tensors of Mn3Ge and Mn3Sn as a function of temperature through their respective antiferromagnetic phase transitions. Large discontinuities in the bulk moduli at the Néel transitions indicate strong magnetoelastic coupling in both compounds. Strikingly, the discontinuities are nearly a factor of 10 larger in Mn3Ge than in Mn3Sn. We use the magnitudes of the discontinuities to calculate the pressure derivatives of the Néel temperature, which are 39 K/GPa 14.3 K/GPa for Mn3Ge and Mn3Sn, respectively.

The nature of the pseudogap phase remains a major puzzle in our understanding of cuprate high-temperature superconductivity. Whether or not this metallic phase is defined by any of the reported broken symmetries, the topology of its Fermi surface remains a fundamental open question. Here we use angle-dependent magnetoresistance (ADMR) to measure the Fermi surface of the La1.6–xNd0.4SrxCuO4 cuprate. Outside the pseudogap phase, we fit the ADMR data and extract a Fermi surface geometry that is in excellent agreement with angle-resolved photoemission data.

Topological semimetals are predicted to exhibit unconventional electrodynamics, but a central experimental challenge is singling out the contributions from the topological bands. TaAs is the prototypical example, where 24 Weyl points and 8 trivial Fermi surfaces make the interpretation of any experiment in terms of band topology ambiguous. We report magneto-infrared reflection spectroscopy measurements on TaAs. We observed sharp inter-Landau level transitions from a single pocket of Weyl Fermions in magnetic fields as low as 0.4 tesla.

We measure the Shubnikov-de Haas effect in thin-film grown on an substrate. We detect all three known Fermi surfaces and extract the Fermi surface volumes, cyclotron effective masses, and quantum lifetimes. We show that the electronic structure is nearly identical to that of single-crystal , and that the quasiparticle lifetime is consistent with the of comparably clean, single-crystal . Unlike single-crystal , where the quantum and transport lifetimes are roughly equal, we find that the transport lifetime is times longer than the quantum lifetime.

A variety of ‘strange metals’ exhibit resistivity that decreases linearly with temperature as the temperature decreases to zero1–3, in contrast to conventional metals where resistivity decreases quadratically with temperature. This linear-in-temperature resistivity has been attributed to charge carriers scattering at a rate given by ħ/τ = αkBT, where α is a constant of order unity, ħ is the Planck constant and kB is the Boltzmann constant.

Two-dimensional (2D) hybrid organic-inorganic perovskites consisting of alternating organic and inorganic layers are a new class of layered structures. They have attracted increasing interest for photovoltaic, optoelectronic, and thermoelectric applications, where knowing their thermal transport properties is critical. We carry out both experimental and computational studies on thermal transport properties of 2D butylammonium lead iodide crystals and find their thermal conductivity is ultralow (below 0.3 W m-1 K-1) with very weak anisotropy (around 1.5) among layered crystals.

In RuCl3, inelastic neutron scattering and Raman spectroscopy reveal a continuum of non-spin-wave excitations that persists to high temperature, suggesting the presence of a spin liquid state on a honeycomb lattice. In the context of the Kitaev model, finite magnetic fields introduce interactions between the elementary excitations, and thus the effects of high magnetic fields that are comparable to the spin-exchange energy scale must be explored.

Sr2RuO4 has stood as the leading candidate for a spin-triplet superconductor for 26 years1. However, recent NMR experiments have cast doubt on this candidacy2,3 and it is difficult to find a theory of superconductivity that is consistent with all experiments. The order parameter symmetry for this material therefore remains an open question. Symmetry-based experiments are needed that can rule out broad classes of possible superconducting order parameters.

Many unconventional superconductors exhibit a common set of anomalous charge transport properties that characterize them as ‘strange metals’, which provides hope that there is a single theory that describes them1–3. However, model-independent connections between the strange metals and superconductivity have remained elusive. Here, we show that the Hall effect of the unconventional superconductor BaFe2(As1−xPx)2 contains an anomalous contribution arising from the correlations within the strange metal.