Neutron Scattering Research on Quantum Materials under Pressure*

Quantum Materials are characterized by an extreme sensitivity to weak external perturbations (H, E, P). Among these, pressure is unique in that, even in a moderate range, it induces structural changes energetically equivalent to thousands of K. In addition, samples subjected to pressure do not suffer from chemical segregation or disorder, characteristic of chemical manipulation. In this context, neutron scattering, with its ability to inspect simultaneously the lattice and spin degrees of freedom, while not depositing any energy, is uniquely suitable for the study of quantum systems. Instruments at modern neutron sources, such as the spallation neutron source, are now fitted with custom made pressure devices, that extend the realm of the possible in neutron scattering of the quantum world. Indeed, the range of pressure, temperature and field available, allow faster measurements on smaller samples. Here we will present the current suite of instrumentation available to research of quantum materials at the SNS, including new developments in instrumentation and pressure devices. These advances will be illustrated with science examples that benefited from these new capabilities.