Abstract
We report the fabrication of hexagonal-boron-nitride (hBN) encapsulated multiterminal WSe2 Hall bars with 2D/2D low-temperature Ohmic contacts as a platform for investigating the two-dimensional (2D) metal-insulator transition. We demonstrate that the WSe2 devices exhibit Ohmic behavior down to 0.25 K and at low enough excitation voltages to avoid current-heating effects. Additionally, the high-quality hBN-encapsulated WSe2 devices in ideal Hall-bar geometry enable us to accurately determine the carrier density. Measurements of the temperature (T) and density (ns) dependence of the conductivity σ(T, ns) demonstrate scaling behavior consistent with a metal-insulator quantum phase transition driven by electron-electron interactions but where disorder-induced local magnetic moments are also present. Our findings pave the way for further studies of the fundamental quantum mechanical properties of 2D transition metal dichalcogenides using the same contact engineering.
| Original language | English |
|---|---|
| Pages (from-to) | 10594-10602 |
| Number of pages | 9 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 13 |
| Issue number | 8 |
| DOIs | |
| State | Published - Mar 3 2021 |
Funding
The work by L.J.S. and D.P. was supported by NSF Grants DMR-1307075 and DMR-1707785 and the National High Magnetic Field Laboratory through the NSF Cooperative Agreement No. DMR-1644779 and the State of Florida. Z.Z. acknowledges support by NSF Grant DMR-2004445. J.Y. and D.M. acknowledge support from the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.
Keywords
- 2D materials
- contact resistance
- field-effect transistor
- metal-insulator transition
- transition metal dichalcogenides
- tungsten diselenide