Abstract
Band structures are vital in determining the electronic properties of materials. Recently, the two-dimensional (2D) semimetallic transition metal tellurides (WTe 2 and MoTe 2 ) have sparked broad research interest because of their elliptical or open Fermi surface, making distinct from the conventional 2D materials. In this study, we demonstrate a centrosymmetric photothermoelectric voltage distribution in WTe 2 nanoflakes, which has not been observed in common 2D materials such as graphene and MoS 2 . Our theoretical model shows the anomalous photothermoelectric effect arises from an anisotropic energy dispersion and micrometer-scale hot carrier diffusion length of WTe 2 . Further, our results are more consistent with the anisotropic tilt direction of energy dispersion being aligned to the b-axis rather than the a-axis of the WTe 2 crystal, which is consistent with the previous first-principle calculations as well as magneto-transport experiments. Our work shows the photothermoelectric current is strongly confined to the anisotropic direction of the energy dispersion in WTe 2 , which opens an avenue for interesting electro-optic applications such as electron beam collimation and electron lenses.
| Original language | English |
|---|---|
| Pages (from-to) | 2647-2652 |
| Number of pages | 6 |
| Journal | Nano Letters |
| Volume | 19 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Apr 10 2019 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2019 American Chemical Society.
ASJC Scopus Subject Areas
- Bioengineering
- General Chemistry
- General Materials Science
- Condensed Matter Physics
- Mechanical Engineering
Keywords
- 2D materials
- anisotropic energy dispersion
- electro-optic applications
- photothermoelectric effect
- WTe crystal