Why 2-D? Measuring thickness-dependent electronic properties
A FLEET study published last week in Physical Review B quantifies the precise transition point in the promising material tungsten ditelluride (WTe2). Measurements found: WTe2 thin films cross from 3-D to 2-D electronic systems at thickness of ~ 20 nm overlap between conduction and valence bands decrease at thickness below ~12 nm, implying that even thinner samples might achieve a bandgap. Angle-dependent quantum oscillation measurements were performed in very high magnetic fields at FLEET CI Alex Hamilton’s lab at UNSW, revealing how the material’s band structure changed with decreasing thickness, with a 3-D–2-D crossover when the sample thickness was reduced below 26 nm. Tungsten ditelluride (WTe2) is a layered, transition metal dichalcogenide with several promising properties: extremely large magnetoresistance, with potential for use in magnetic sensors bulk WTe2 predicted to be a type-II Weyl semimetal monolayer WTe2 is a high temperature topological insulator, a superconductor, and a ferroelectric. We refer to TMDs as ‘2-D’ because of this layered crystal structure.