Coexisting Charge-Ordered States with Distinct Driving Mechanisms in Monolayer VSe₂

Thinning crystalline materials to two dimensions (2D) creates a rich playground for electronic phases, including charge, spin, superconducting, and topological order. Bulk materials hosting charge density waves (CDWs), when reduced to ultrathin films, have shown CDW enhancement and tunability. However, charge order confined to only 2D remains elusive. Here we report a distinct charge ordered state emerging in the monolayer limit of 1T-VSe2. Systematic scanning tunneling microscopy experiments reveal that bilayer VSe2 largely retains the bulk electronic structure, hosting a tridirectional CDW. However, monolayer VSe2 -consistently across distinct substrates-exhibits a dimensional crossover, hosting two CDWs with distinct wavelengths and transition temperatures. Electronic structure calculations reveal that while one CDW is bulk-like and arises from the well-known Peierls mechanism, the other is decidedly unconventional. The observed CDW-lattice decoupling and the emergence of a flat band suggest that the second CDW could arise from enhanced electron-electron interactions in the 2D limit. These findings establish monolayer-VSe2 as a host of coexisting charge orders with distinct origins, and enable the tailoring of electronic phenomena via emergent interactions in 2D materials

An investigation of the surface reactivity of aluminium and gallium precursors for thin film growth

SIGLEAvailable from British Library Document Supply Centre- DSC:D78815 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Ultralow-energy SIMS for shallow semiconductor depth profiling

10.1016/j.apsusc.2008.05.030Applied Surface Science25541307-1310ASUS

Sub-keV secondary ion mass spectrometry depth profiling: Comparison of sample rotation and oxygen flooding

10.1016/j.apsusc.2004.03.136Applied Surface Science231-232653-657ASUS

Synchrotron PES and NEXAFS studies of self-assembled aromatic thiol monolayers on Au(1 1 1)

10.1016/j.elspec.2009.02.015Journal of Electron Spectroscopy and Related Phenomena1721-354-63JESR

Narrow surface transient and high depth resolution SIMS using 250 eV O2 +

10.1016/j.apsusc.2006.02.198Applied Surface Science252197243-7246ASUS

Molecular interactions on epitaxial graphene

10.1088/0031-8949/2012/T146/014007Physica ScriptaT146-PHST

XPS investigation of the oxidation/corrosion of melt-spun Mg

10.1016/S0169-4332(99)00593-0Applied Surface Science1581112-119ASUS

6H-SiC(0 0 0 1) phase transition: Evolution of the (6 × 6) magic clusters

10.1016/j.susc.2004.03.062Surface Science5581-3145-158SUSC