The topic tells me that if you heat carbon at atmospheric pressure it eventually turns directly into a gas without being liquid first.
At what pressure can you make liquid carbon?
Has anyone actually ever studied liquid carbon?
Surprisingly a web search did not answer these questions.
The carbon phase diagram shows that liquid carbon is only achievable at high pressure (~100 atm) and high temperature (~4500 K).
This means that liquid carbon probably has very limited applications, and not many will be researching it. Funding is hard to come by when the applications of the research are not apparent.