Extrinsic Surface States
Surface states originating from clean and well ordered surfaces are usually called intrinsic. These states include states originating from reconstructed surfaces, where the two-dimensional translational symmetry gives rise to the band structure in the k space of the surface.
Extrinsic surface states are usually defined as states not originating from a clean and well ordered surface. Surfaces that are fit into the category extrinsic are :
- Surfaces with defects, where the translational symmetry of the surface is broken.
- Surfaces with adsorbates
- Interfaces between two material such as a semiconductor-oxide or semiconductor-metal interfaces
- Interfaces between solid and liquid phases.
Generally for extrinsic surface states is that they cannot easily be characterized in terms of their chemical, physical or structural properties.
Read more about this topic: Surface States
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