Observations of Charge-Density-Wave States in W₆Te₆ Wires

Abstract

Determining the electronic ground state of a one-dimensional system is crucial to understanding the underlying physics of electronic behavior. Here, we demonstrate the discovery of charge-density wave states in few-wire W 6 Te 6 arrays using scanning tunneling microscopy/spectroscopy. We directly visualize incommensurate charge orders, energy gaps with prominent coherence peaks, and the picometer-scale lattice distortion in nearly disorder-free doublewire systems, thereby demonstrating the existence of Peierls-type charge density waves. In the presence of disorder-induced charge order fluctuations, the coherence peaks resulting from phase correlation disappear and gradually transform the system into the pseudogap states. The power-law zero-bias anomaly and quasi-particle interference analysis further suggest the Tomonaga−Luttinger liquid behavior in such pseudogap region. In addition, we explicitly determined the evolution of the CDW energy gap as a function of stacking-wire numbers. The present study demonstrates the existence of electron−phonon interactions in few-wire W 6 Te 6 that can be tuned by disorders and van der Waals stacking.

van der Waals Engineering of Charge Density Waves in One-Dimensional Nb6Te6 Nanowires

“…A more marked difference between the Nb 6 Te 6 SW and the formerly studied TMM wire lies in its electronic structure. In some pioneering works, such as those involving Mo 6 Se 6 bundles and W 6 Te 6 arrays, 1D charge order was observed due to strong electron–phonon coupling. However, the role of the CDW in isolated single TMM wires has remained elusive.…”

“…By applying a Gaussian filter to average the contribution of the lattice modulation, I filter ≈ A r A m e i q × u false( r false) 2 . Then, we can extract the distortion field u ( r ) …”

“…In some pioneering experimental studies of TMM wires, 1D correlated quantum states have been found. For instance, behaves like TLL in edge-attached Mo 6 Se 6 wires and Mo 6 Te 6 arrays, CDW orders in Mo 6 Se 6 wires, and in our recent work on double W 6 Te 6 wire arrays, which also exhibit complex competition between the TLL and CDW phases regulated by local disorders . However, the emergence of charge orders in a more ideal 1D situation, namely, a single isolated TMM wire, is yet to be observed because of the complex environmental settings and semiconducting nature of some single TMM wires.…”

“…For instance, behaves like TLL in edge-attached Mo 6 Se 6 wires 35 and Mo 6 Te 6 arrays, 36 CDW orders in Mo 6 Se 6 wires, 29 and in our recent work on double W 6 Te 6 wire arrays, which also exhibit complex competition between the TLL and CDW phases regulated by local disorders. 31 However, the emergence of charge orders in a more ideal 1D situation, namely, a single isolated TMM wire, is yet to be observed because of the complex environmental settings and semiconducting nature of some single TMM wires. The flexibility and efficiency of vdW interactions in tuning subtle electronic behaviors have also rarely been demonstrated in 1D many-body physics.…”

“…High-throughput calculations have also predicted the stability of several tens of TMM compositions, which host various band structures (metal/semiconductor), magnetism, and device functionalities . To date, experimental realizations of TMM materials have focused predominantly on W- and Mo-based compositions − and have been achieved through chemical dissolution, , physical vapor deposition, ,,, and electron-beam irradiation. ,,, Some of these systems can even disperse into individual wires, such as single Mo 6 Te 6 wires encapsulated by CNTs; single Mo 6 Se 6 , Mo 6 S 6 , and W 6 Se 6 wires achieved by etching 2D TMD layers; , and single W 6 Te 6 wires grown by molecular beam epitaxy (MBE) . In some pioneering experimental studies of TMM wires, 1D correlated quantum states have been found.…”