3 research outputs found
Strain Engineering a Charge Density Wave Phase in Transition Metal Dichalcogenide 1T-VSe
We report a rectangular charge density wave (CDW) phase in strained
1T-VSe thin films synthesized by molecular beam epitaxy on c-sapphire
substrates. The observed CDW structure exhibits an unconventional rectangular
4a{\times}{\sqrt{3a}} periodicity, as opposed to the previously reported
hexagonal structure in bulk crystals and exfoliated thin layered
samples. Tunneling spectroscopy shows a strong modulation of the local density
of states of the same CDW periodicity and an energy gap of
meV. The CDW energy gap evolves into a full gap at
temperatures below 500 mK, indicating a transition to an insulating phase at
ultra-low temperatures. First-principles calculations confirm the stability of
both and structures arising from soft modes in
the phonon dispersion. The unconventional structure becomes preferred in the
presence of strain, in agreement with experimental findings