Science Advances

Supplementary Materials

This PDF file includes:

  • Section S1. Electrical transport behavior of WTe2 single-crystal samples in c-AFM
  • Section S2. Ellipsometry measurements on a WTe2 single-crystal
  • Section S3. Electrical transport behavior of WTe2 thin films in a capacitor geometry
  • Section S4. Polarization switching in the metal-gated WTe2 thin film sample
  • Section S5. Piezoelectric coefficient of WTe2
  • Section S6. Calculation of Debye length of WTe2
  • Section S7. Extrinsic mechanisms as the origin of PFM response in WTe2?
  • Table S1. The calculated piezoelectric constant e3i (C/m2) and d3i (pm/V) for WTe2 with a polarization along +z direction.
  • Fig. S1. Spectroscopic current-bias curves recorded in c-AFM mode on a pristine surface of a freshly cleaved WTe2 single-crystal sample in a controlled N2 environment.
  • Fig. S2. Ellipsometry measurements determining the thickness of the surface oxide on WTe2.
  • Fig. S3. Current-bias characteristics of metal-gated WTe2 thin film samples.
  • Fig. S4. Polarization switching in a metal-gated WTe2 thin film sample.
  • Fig. S5. The polarization change ∆P with respect to the strain ξ along z direction.
  • Fig. S6. The calibrated piezoresponse measurements versus bias for a metal-gated WTe2 thin film sample.
  • Fig. S7. Stable ferroelectric domains in a WTe2 single crystal.
  • References (5862)

Download PDF

Files in this Data Supplement: