Dai's research primarily focuses on experimental condensed matter physics, using neutrons as a probe to study correlated electron materials. His works include direct evidence for
magnetism and
superconductivity coupling in unconventional superconductors, topological spin excitations in different classes of
quantum materials and discoveries in the magnetic properties of
cuprate and
iron-based superconductors. Dai established 'Pengcheng Dai's group' at Rice University's Physics Department, which conducts research on condensed matter physics and also founded a materials growth laboratory that produces high-quality single crystals of correlated electron materials.
Cuprate superconductors In 1998, he demonstrated the incommensurate spin fluctuations in the YBa2Cu3O6+x (YBCO) system, observed the resonance in underdoped YBCO and studied the effects of magnetic field on the resonance, and characterized the overall energy/wave vector dependence of the magnetic excitations in YBCO. Later, in 2000, he discovered one-dimensional nature of spin fluctuations. He has also worked on electron-doped cuprates. He clarified the microscopic origin of the annealing process, studied the electron-magnetic excitation coupling and discovered resonance in the electron-doped high-transition-temperature superconductor Pr0.88LaCe0.12CuO4−δ.
Iron-based superconductors Over the past 15 years, along with his research group, Dai has made contributions to describe the interplay between magnetism and superconductivity and has published more than 150 papers in the field. In 2008, they determined the antiferromagnetic structure in the parent compound of one class of iron-based superconductors. Afterwards, he mapped out the electronic phase diagram of these materials and carried out the first
spin wave measurements to determine the effective Heisenberg Hamiltonian for the parent compounds of three families of iron-based superconductors. His research in 2014 led to the discovery of the first evidence for a spin nematic phase, accomplished by analyzing the evolution of overall spin excitations across the nematic
phase transition temperature determined by transport measurements. His group also developed a cleaver detwinned device that allowed systematic measurements of magnetism in iron-based superconductors in the intrinsically detwinned state.
Fermion superconductors In addition to cuprate and iron-based superconductors, Dai has worked on comprehending the interplay between magnetism and superconductivity in heavy fermion superconductors. This includes the discovery of upward dispersion in neutron resonance of CeCoIn5, mapping of overall spin excitations in CeCu2Si2, and antiferromagnetic spin fluctuations are coupled with superconductivity of spin-triplet candidate UTe2. His discovery of an antiferromagnetic neutron spin resonance in spin-triplet superconductor candidate UTe2 is particularly important because it suggests that superconductivity in spin-triplet superconductors may also be driven by antiferromagnetic spin fluctuations instead of ferromagnetic spin fluctuations ==Awards and honors==