Courtesy of the Daily Grail, here's an article from Quanta Magazine about the "strange metal" phase of some materials near the condition of high-temperature superconductivity. It's suggested that in this phase huge numbers of electrons become entangled with one another, "leading to a whole state of matter":
https://www.theatlantic.com/science/arch...it/576484/
https://www.theatlantic.com/science/arch...it/576484/