Epitaxial HfTe2 Dirac semimetal in the 2D limit

Abstract

One monolayer semimetallic HfTe2 thin films are grown on three substrates with different electronic properties in order to study the substrate effect on the electronic structure of the HfTe2 epilayer. Angle resolved photoelectron spectroscopy measurements indicate that the band features are identical in all three cases, providing evidence that the HfTe2 epilayer does not interact with any of the substrates to form hybridized bands and any band feature originates from the HfTe2 material itself. However, a shift of HfTe2 energy bands is observed among the three cases, which is attributed to substrate electron doping. This paves the way for accessing the Dirac point of HfTe2 Dirac semimetal, which is located about ∼0.2 to 0.3 eV above the Fermi level in the case of suspended HfTe2 in a non-destructive way.

Two‐Dimensional Van Der Waals Topological Materials: Preparation, Properties, and Device Applications

“…Compare to the WSM, the DSM is protected by both the time-reversal symmetry and space-reversal symmetry. VdW PtSe 2 , [101] PtTe 2 , [102] PdTe 2 , [103] NiTe 2 , [104] ZrTe 2 , [105] ZrTe 5 , [106] HfTe 2 , [107] and HfTe 5 [108] are all identified to type-II DSM. Currently, 2D vdW TSMs have various potential applications in electronics, ferroelectrics, thermoelectrics, spintronics, optoelectronics, electrochemistry, etc (Table 1).…”