Final answer:
p-like or s-like band structures refer to energy bands in solids that stem mainly from atomic p or s orbitals. S orbitals contribute to more delocalized and lower energy bands, while p orbitals lead to higher energy bands that may have directional characteristics.
Step-by-step explanation:
When people refer to p-like or s-like band structures in the context of solid-state physics, they are describing the energy bands that arise primarily from the atomic p or s orbitals. s orbitals are spherical and contribute to more delocalized and lower energy bands, while p orbitals are d*mbbell-shaped and can contribute to bands that are typically higher in energy and can have directional properties depending on the crystal structure of the material. In contrast, d or f orbitals, which have more complex shapes, tend to form more localized energy bands within the solid.
To distinguish between these types of bands, one can look at the properties of materials and their band structures obtained from experiments such as photoelectron spectroscopy or calculations such as density functional theory. In metals and semiconductors, while the states do mix to some extent, s-like bands tend to show a more constant energy across the Brillouin zone, whereas p-like bands tend to show a significant variation in energy with crystal momentum. For d and f states, the localization is often higher, and these states can contribute to magnetic behavior and localized states within the band structure.
Understanding the nature of band gaps and band character is crucial for determining the electronic properties of materials. For example, semiconductors have a small but finite band gap which allows electrons to be moved from the valence band to the conduction band with some amount of energy, typically from thermal excitation, whereas insulators have a large band gap, making electron movement and thus electrical conduction much less probable.