Room Temperature Commensurate Charge Density Wave in Epitaxial Strained TiTe2 Multilayer Films. Issue 5 (28th January 2019)

• Record Type: Journal Article
• Authors: Fragkos, Sotirios; Sant, Roberto; Alvarez, Carlos; Bosak, Alexei; Tsipas, Polychronis; Tsoutsou, Dimitra; Okuno, Hanako; Renaud, Gilles; Dimoulas, Athanasios
• Is Part Of: Advanced materials interfaces. Volume 6:Issue 5(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-01-28
• Subjects: 2D materials -- charge density wave -- molecular beam epitaxy -- room temperature -- titanium ditelluride; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201801850
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: The group IVB 2D transition metal dichalcogenides are considered to be stable in the high symmetry trigonal octahedral structure due to the lack of unpairedd ‐electrons on the metal site. It is found that multilayer epitaxial TiTe2 is an exception adopting a commensurate 2 × 2 × 2 charge density wave (CDW) structure at room temperature with an ABA type of stacking as evidenced by direct lattice imaging and reciprocal space mapping. The CDW is stabilized by highly anisotropic strain imposed by the substrate with an out‐off‐plane compression which reduces the interlayer van der Waals gap increasing the coupling between TiTe2 layers. A weaker 2 × 2 CDW is also confirmed at room temperature for epitaxial monolayer TiTe2 . The addition of epitaxial strained TiTe2 to the family of CDW materials will enable real world applications that take advantage of a CDW ground state at room temperature. Abstract : The phase diagram of multilayer TiTe2 contains a commensurate 2 × 2 × 2 charge density wave (CDW) state under nonhydrostatic stress, which can be realized under ambient pressure conditions due to the influence of the substrate in epitaxial thin films. The CDW is stabilized at, and above, room temperature so it is expected to enable real world applications.