On top of silicon, metal conducts (5)
I believe the answer is:
leads
'conducts' is the definition.
('lead' can be a synonym of 'conduct')
'on top of silicon metal' is the wordplay.
'on top of' says to put letters next to each other.
'silicon' becomes 's' (this might be a standard abbreviation which I don't know about).
'metal' becomes 'lead' (lead is a kind of metal).
's' put after 'lead' is 'LEADS'.
Can you help me to learn more?
(Other definitions for leads that I've seen before include "Actors who play principal roles" , "Goes ahead" , "What Prime Minister does" , "Clues" , "stars" .)