  The discovery of a record high superconducting transition temperature (Tc) of
288 K in a pressurized hydride inspires new hope to realize ambient condition
superconductivity. Here, we give a perspective on the theoretical and
experimental studies of hydride superconductivity. Predictions based on the
BCS-Eliashberg-Midgal theory with the aid of density functional theory have
been playing a leading role in the research and guiding the experimental
realizations. To date, about twenty hydrides experiments have been reported to
exhibit high-Tc superconductivity and their Tc agree well with the predicted
values. However, there are still some controversies existing between the
predictions and experiments, such as no significant transition temperature
broadening observed in the magnetic field, the experimental electron-phonon
coupling beyond the Eliashberg-Midgal limit, and the energy dependence of
density of states around the Fermi level. To investigate these controversies
and the origin of the highest Tc in hydrides, key experiments are required to
determine the structure, bonding, and vibrational properties associated with H
atoms in these hydrides.
