Bulk and surface electronic states in the dosed semimetallic HfTe2

Abstract

The dosing of layered materials with alkali metals has become a commonly used strategy in ARPES experiments. However, precisely what occurs under such conditions, both structurally and electronically, has remained a matter of debate. Here we perform a systematic study of 1T-HfTe 2 , a prototypical semimetal of the transition metal dichalcogenide family. By utilizing photon energy-dependent angle-resolved photoemission spectroscopy (ARPES), we have investigated the electronic structure of this material as a function of potassium (K) deposition. From the k z maps, we observe the appearance of 2D dispersive bands after electron dosing, with an increasing sharpness of the bands, consistent with the wave-function confinement at the topmost layer. In our highest-dosing cases, a monolayerlike electronic structure emerges, presumably as a result of intercalation of the alkali metal. Here, by bringing the topmost valence band below E F , we can directly measure a band overlap of ∼0.2 eV. However, 3D bulklike states still contribute to the spectra even after considerable dosing. Our work provides a reference point for the increasingly popular studies of the alkali metal dosing of semimetals using ARPES.

Type-III Dirac fermions in HfxZr1−xTe2 topological semimetal candidate

“…This is also in contrast to what is observed in the band structure of HfTe2 and ZrTe2 bulk single crystals imaged by synchrotron ARPES. [19][20][21][22] This difference may be attributed to a substrate induced effect in epitaxial few-layer film. value similar to that obtained in the case of HfTe2 and ZrTe2 epitaxial films.…”

“…Synchrotron ARPES studies on single crystals of K and Cr doped HfTe2 19,20 and ZrTe2, 21 respectively, show no clear signs of Dirac-like features compared to the epitaxially grown films, 17,18 while others, by combining synchrotron ARPES 22 on 1T-ZrTe2 single crystals with DFT This is the author's peer reviewed, accepted manuscript. However, the online version of record will be different from this version once it has been copyedited and typeset.…”

Surface Electronic Structure Engineering of Manganese Bismuth Tellurides Guided by Micro‐Focused Angle‐Resolved Photoemission

“…An alternative strategy that solves this problem is based on dosing alkali metals, such as Li, K, Rb, or Cs, on the material surface while collecting ARPES spectra, which has been demonstrated on a range of semimetals [ 36–38 ] and semiconductors. [ 39–42 ] In the simplest approximation, the adsorbed alkali metals provide electron doping at the surface of the materials with the effect of merely shifting the chemical potential.…”

“…[30][31][32][33][34] A downside of Sb substitution is that the doping cannot be monitored in situ but requires synthesis of multiple different crystals, leading to large sample variability between different experiments. [35] An alternative strategy that solves this problem is based on dosing alkali metals, such as Li, K, Rb, or Cs, on the material surface while collecting ARPES spectra, which has been demonstrated on a range of semimetals [36][37][38] and semiconductors. [39][40][41][42] In the simplest approximation, the adsorbed alkali metals provide electron doping at the surface of the materials with the effect of merely shifting the chemical potential.…”

Fermiology and electron-phonon coupling in the 2H and 3R polytypes of NbS$\boldsymbol{_2}$

“…1(c) and 1(g)). This is a helpful representation of the DFT band structure for comparison with ARPES measurements, due to the non-conservation of k z in the photoemission process, which leads to an effective integration over a range of k z values [25,[31][32][33]. In the overview ARPES spectra of the 2H phase in Fig.…”