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Local Real-Space View of the Achiral 1T-TiSe_{2} 2×2×2 Charge Density Wave
B Hildebrand1, T Jaouen1, M-L Mottas1
1Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, CH-1700 Fribourg, Switzerland.
Physical Review Letters
|April 26, 2018
Summary
This study reveals the 3D structure of charge density waves in 1T-TiSe2 using advanced scanning tunneling microscopy. It clarifies the achiral nature of the wave, contradicting previous helical stacking claims.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Surface Science
Background:
- 1T-TiSe2 is a 2D layered material known to exhibit charge density wave (CDW) transitions.
- Previous studies suggested helical stacking and chiral order in its CDW state.
- Understanding the 3D character of lattice distortions is crucial for CDW materials.
Purpose of the Study:
- To probe the three-dimensional (3D) character of the periodic lattice distortion (PLD) in 1T-TiSe2.
- To investigate the spatial nature of the charge density wave (CDW) transition.
- To clarify the stacking order and symmetry of the CDW in 1T-TiSe2.
Main Methods:
- Utilizing scanning tunneling microscopy (STM) with intentionally introduced interstitial Ti atoms.
- Achieving enhanced spatial resolution to probe beyond the surface.
- Analyzing the 3D structure of the periodic lattice distortion (PLD).
Main Results:
- The 3D character of the weak periodic lattice distortion (PLD) associated with the CDW transition was successfully probed.
- The charge density wave (CDW) in the z direction was revealed to be inversion-symmetric and achiral.
- Evidence contradicting the existence of helical CDW stacking and chiral order was obtained.
Conclusions:
- The study provides a new method for simultaneously probing charge and structural reconstructions in CDW materials.
- The findings clarify the symmetry of the CDW in 1T-TiSe2, challenging prior interpretations.
- This work opens avenues for detailed 3D characterization of CDW phenomena.
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