APS Fellowships are granted in recognition of outstanding achievement and contribution to physics. Less than half of one percent of the membership of the Society may become Fellows in a given year. Gehring's citation states:
"For major contributions to our understanding of the lattice dynamics of relaxor ferroelectrics, and elucidating the nature of the spin dynamics of cuprate oxides by means of neutron scattering."
Peter Gehring's most noteworthy work has involved two different classes of oxide materials. His recent research centers on the lattice dynamics and intrinsic structural distortions of relaxor ferroelectrics. These are materials that form nanoscale droplets of ferroelectric order, which strongly distort both the underlying lattice structure and the phonon spectrum. Peter’s work has elucidated how these droplets affect the ferroelectricity by exploring the diffuse scattering and lattice dynamics as a function of temperature, applied electric field, and stoichiometry. This recent research is already having a very high impact on the field. His earlier work consisted of pioneering investigations of the magnetic order and spin dynamics of both hole-doped and electron-doped cuprate superconductors. Initial studies focused on the spin dynamics of optimally doped (La-Sr)2CuO4, where it was found that strong spin fluctuations persist into the superconducting state, and form an essential part of the fundamental physical description of this important class of materials. These investigations were extended to the lightly doped side of the phase diagram to elucidate how the long range order of the parent Mott insulator evolves into the magnetic fluctuations that dominate the magnetism in the superconducting regime. Soon after the electron-doped systems were discovered, Peter and collaborators studied the magnetic order and spin dynamics of these new systems. Work then expanded into the bilayer system (YBCO), the lattice dynamics, and the nature of the intrinsic structural and magnetic inhomogeneities, forming an impressive body of published research that is very heavily cited.
