This is based on a bismuth oxyselenide (Bi₂O₂Se) monolayer, called "2D" as opposed to bulk silicon.<p><a href="https://hn.algolia.com/?dateRange=all&page=0&prefix=false&query=bismuth&sort=byDate&type=all" rel="nofollow">https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...</a>