## surface states

https://doi.org/10.1351/goldbook.S06190
Energy levels localized in the @S06187@ of semiconductors, which do not bear any direct relation to the bulk energy distribution, but which can exchange electrons with the bulk. In such a case a @S05776@ may arise even when $$\sigma$$ (the free @C00988@) is zero, i.e. $$\sigma =\sigma _{\mathrm{sc}}+\sigma _{\mathrm{ss}}$$, where $$\sigma _{\mathrm{sc}}$$ is the space @C00988@ and $$\sigma _{\mathrm{ss}}$$ is the @C00988@ associated with the surface states.
Source:
PAC, 1986, 58, 437. (Interphases in systems of conducting phases (Recommendations 1985)) on page 443 [Terms] [Paper]