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Sub-picosecond photo-induced displacive phase transition in two-dimensional MoTe$_2$
- Source :
- npj 2D Materials and Applications, Vol 4, Iss 1, Pp 1-8 (2020)
- Publication Year :
- 2019
-
Abstract
- Photo-induced phase transitions (PIPTs) provide an ultrafast, energy-efficient way for precisely manipulating the topological properties of transition-metal ditellurides, and can be used to stabilize a topological phase in an otherwise semiconducting material. Using first-principles calculations, we demonstrate that the PIPT in monolayer MoTe$_2$ from the semiconducting 2H phase to the topological 1T$'$ phase can be triggered purely by electronic excitations that soften multiple lattice vibrational modes. These softenings, driven by a Peierls-like mechanism within the conduction bands, lead to structural symmetry breaking within sub-picosecond timescales, which is shorter than the timescale of a thermally driven phase transition. The transition is predicted to be triggered by photons with energies over $1.96$\,eV, with an associated excited carrier density of $3.4\times10^{14}$\,cm$^{-2}$, which enables a controllable phase transformation by varying the laser wavelength. Our results provide insight into the underlying physics of the phase transition in 2D transition-metal ditellurides, and show an ultrafast phase transition mechanism for manipulation of the topological properties of 2D systems.<br />3
- Subjects :
- Phase transition
Photon
Materials science
FOS: Physical sciences
02 engineering and technology
01 natural sciences
Molecular physics
4016 Materials Engineering
lcsh:Chemistry
4009 Electronics, Sensors and Digital Hardware
0103 physical sciences
Monolayer
lcsh:TA401-492
General Materials Science
010306 general physics
40 Engineering
Condensed Matter - Materials Science
Mechanical Engineering
Materials Science (cond-mat.mtrl-sci)
General Chemistry
021001 nanoscience & nanotechnology
Condensed Matter Physics
Wavelength
lcsh:QD1-999
Mechanics of Materials
Excited state
Picosecond
Molecular vibration
lcsh:Materials of engineering and construction. Mechanics of materials
7 Affordable and Clean Energy
0210 nano-technology
Ultrashort pulse
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- npj 2D Materials and Applications, Vol 4, Iss 1, Pp 1-8 (2020)
- Accession number :
- edsair.doi.dedup.....513817eaa171782b537ddd3ed078f761