Disentangling surface conducting and bulk insulating behaviour in a d-electron topological insulator

Transport measurements in f-electron insulators have revealed a new class of materials with conducting surface states of potential topological character. Strong electron-electron interactions in these materials allow for 2D electron physics to be explored in a bulk system. An open question remains as to whether these conducting surface states can exist in the absence of heavy f-electron physics. Experimental results are presented for transport measurements on a d-electron topological insulator candidate. Signatures of a conducting surface state are found for temperatures ⪅ 5 K and seen to vanish at higher temperatures. A new paradigm in which conducting surface states emerge due to strong electron-electron interactions and potential topological effects in d-electron systems is discussed.