5308
A central issue for copper oxides is the nature of the insulating ground state at low carrier densities and the emergence of high - temperature superconductivity from that state with doping .
 Chemical: copper oxides
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: copper oxides