https://doi.org/10.1351/goldbook.S05591
Material whose @C01245@, due to charges of both signs, is normally in the range between that of metals and insulators and in which the @E01923@ @C00859@ density can be changed by external means.
Source:
PAC, 1982, 54, 1533. (Glossary of terms used in nuclear analytical chemistry (Provisional)) on page 1552 [Terms] [Paper]