Dimensionality reduction and band quantization induced by potassium intercalation in 1$T$-HfTe${}_2$

Abstract

We have performed angle-resolved photoemission spectroscopy on transition-metal dichalcogenide 1$T$-HfTe${}_2$ to elucidate the evolution of electronic states upon potassium (K) deposition. In pristine HfTe${}_2$, an in-plane hole pocket and electron pockets are observed at the Brillouin-zone center and corner, respectively, indicating the semimetallic nature of bulk HfTe${}_2$, with dispersion perpendicular to the plane. In contrast, the band structure of heavily K-dosed HfTe${}_2$ is obviously different from that of bulk, and resembles the band structure calculated for monolayer HfTe${}_2$. It was also observed that lightly K-dosed HfTe${}_2$ is characterized by quantized bands originating from bilayer and trilayer HfTe${}_2$, indicative of staging. The results suggest that the dimensionality-crossover from 3D (dimensional) to 2D electronic states due to systematic K intercalation takes place via staging in a single sample. The study provides a new strategy for controlling the dimensionality and functionality of novel quantum materials.

7 pages, 4 figures

References in corpus (7)

• Two Dimensional Atomic Crystals
• Valley polarization in MoS2 monolayers by optical pumping
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• The Valley Hall Effect in MoS2 Transistors
• Observation of the Quantum Spin Hall Effect up to 100 Kelvin in a Monolayer Crystal
• Universal Mechanism of Band-Gap Engineering in Transition-Metal Dichalcogenides
• Molecular Beam Epitaxy of thin HfTe2 semimetal films