Reconcile the Bulk Metallic and Surface Insulating state in 1T-TaSe${}_2$

Abstract

The transition metal dichalcogenides 1T-TaS${}_2$ and 1T-TaSe${}_2$ have been extensively studied for the complicated correlated electronic properties. The origin of different surface electronic states remains controversial. We apply scanning tunneling microscopy and spectroscopy to restudy the surface electronic state of bulk 1T-TaSe${}_2$. Both insulating and metallic states are identified in different areas of the same sample. The insulating state is similar to that in 1T-TaS${}_2$, concerning both the dI/dV spectrum and the orbital texture. With further investigations in single-step areas, the discrepancy of electronic states is found to be associated with different stacking orders. The insulating state is most possibly a single-layer property, modulated to a metallic state in some particular stacking orders. Both the metallic and large-gap insulating spectra, together with their corresponding stacking orders, are dominant in 1T-TaSe${}_2$. The connected metallic areas lead to the metallic transport behavior. We then reconcile the bulk metallic and surface insulating state in 1T-TaSe${}_2$. The rich phenomena in 1T-TaSe${}_2$ deepen our understanding of the correlated electronic state in bulk 1T-TaSe${}_2$ and 1T-TaS${}_2$.

8 pages, 7 figures

References in corpus (6)

• Band insulator to Mott insulator transition in 1T-TaS${}_2$
• Distinguishing a Mott Insulator from a Trivial Insulator with Atomic Adsorbates
• Effect of Stacking Order on the Electronic State of 1T-TaS${}_2$
• Possible strain induced Mott gap collapse in 1T-TaS${}_2$
• Identification of the Mott insulating CDW state in 1T-TaS${}_2$
• Doublon-like excitations and their phononic coupling in a Mott charge-density-wave system

Cited by in corpus (7)

• Effect of Stacking Order on the Electronic State of 1T-TaS${}_2$
• Exploring the Charge Density Wave phase of 1$T$-TaSe${}_2$: Mott or Charge-transfer Gap?
• Modified interlayer stacking and insulator to correlated-metal transition driven by uniaxial strain in 1$T$-TaS${}_2$
• Observation of a multitude of correlated states at the surface of bulk 1T-TaSe${}_2$ crystals
• Nature of metallic and insulating domains in the CDW system 1T-TaSe2
• Interlayer Hopping between Surface Mott Insulator and Bulk Band Insulator in layered 1T-TaS_{2}
• Emergent quantum phenomena in two-dimensional 1T-TaS2