Iop Journals

A seemingly still crystal is alive with synchronized atomic motions. Now, angular momentum has been observed flowing coherently between distinct lattice vibrational modes, revealing a hidden propagation of rotational features inside the crystal.

How angular momentum is exchanged and conserved among lattice modes has been difficult to measure experimentally, but has now been observed via a coherent three-phonon scattering process in a topological insulator.

That author's affiliation: Durham University Institution (first & last author): Durham University

We present a first-principles investigation of the spin-ice state in Dy2Ti2O7 using a magnetic source-free exchange and correlation (xc) functional, implemented in the Castep electronic-structure code. By comparing results from the conventional local spin-density approximation, we show that a spin-ice state in Dy2Ti2O7 can be reliably obtained by removing the magnetic sources from the xc contributions to the potential, and we contrast this against the computed ground states of other frustrated pyrochlore magnets.

That author's affiliation: Southern University of Science and Technology Institution (first & last author): Southern University of Science and Technology

Massive spatial superpositions are a resource for quantum interferometry, but it has been hard to generate them beyond single atoms. Now spatially entangled massive states are realized through the tunnelling of atomic clusters in optical lattices.

That author's affiliation: UNSW Sydney First author institution: UNSW Sydney Last author institution: University of Canberra

A tunable artificial crystal in a shallow GaAs quantum well is shown to enable interaction-driven insulating behaviour. Electrostatic control tunes the band structure from graphene-like to kagome-like bands.