Surface oxidation changes transport in thin MoTe₂
Exposed flakes tended toward insulating transport, while protected flakes exhibited a low-temperature superconducting transition.
Yuan Gan, Liyuan Zhang and colleagues compared exposed 1T′-MoTe₂ flakes with flakes protected by hexagonal boron nitride. Thinner unprotected samples showed increasingly insulating transport and suppressed magnetoresistance. Protected samples could still undergo a superconducting transition at low temperature.
To separate thickness effects from surface chemistry, the authors compared transport measurements with in situ scanning tunnelling microscopy and band calculations. The combined evidence pointed to surface oxidation as a cause of gap opening and altered conduction.