Reconfiguration of charge density waves by surface nanostructures onTaS2

Abstract

The transition metal dichalcogenide 1T-TaS 2 forms charge density waves due to the quasi-twodimensionality of its electronic structure. Here we show how the growth of Rb nanowires on the surface of 1T-TaS 2 affects the superstructure of the charge density waves. Scanning tunneling microscopy and lowenergy electron diffraction studies show the replacement of the normal TaS 2 room temperature ͱ13ϫͱ13 phase by c(2ͱ3ϫ4)rect. and 3ϫ3 superstructures depending on the state of nanowire growth. Furthermore, angle resolved photoemission studies give evidence for a metal to semiconductor transition when the superstructure of the charge density wave is changed. These changes are discussed in the context of nanowire growth, which is accompanied by a change in the dimensionality of the electronic states of 1T-TaS 2 .

Strain engineering a 4a×√3a charge-density-wave phase in transition-metal dichalcogenide 1T−VSe2Zhang1, Ha2, Baek3 et al. 2017Phys. Rev. Materials513340View full textAdd to dashboardCite

“…An alternative route to modify the CDW structure is intercalation that can change the electronic structure and induce strain. 1T-TaS2 is a case in point, as a new rectangular 𝑐𝑐(2√3𝑎𝑎 ×4𝑎𝑎) structure is formed from the intercalation of alkali metals such as Na and Rb [41][42][43][44][45], similar to that found in the strained 1T-VSe2 studied here.…”

The Instability of the NbTe2 Surface Structure

“…LEED also shows very well charge density wave (CDW) formation in 1T-TaS 2 and 1T-TaSe 2 . Recently, the dependence of the CDW phases in these compounds on the function of intercalation [9,10] and surface nanostructuring [11,12] was studied in detail. On the contrary, no LEED studies of NbTe 2 or any other corrugated MX 2 compound were reported so far.…”

Electronic structure of exfoliated millimeter-sized monolayer WSe2 on silicon wafer

“…Besides these two near-E F bands, a non-dispersive band marked by a horizontal green line, appears at ~ 0.5eV binding energy. It sits on the same energy level as that in Rb metal, where a density-of-state extreme exists [50,51]. It is reasonable to attribute such a flat band to an impurity band from the scattered Rb cluster on monolayer WSe 2 surface.…”