Intrinsic Phonon Bands in High-Quality Monolayer T' Molybdenum Ditelluride

Abstract

The topologically nontrivial and chemically functional distorted octahedral (T') transition metal dichalcogenides (TMDCs) are a type of layered semimetal that has attracted significant recent attention. However, the properties of monolayer (1L) T'-TMDC, a fundamental unit of the system, is still largely unknown due to rapid sample degradation in air. Here we report that well-protected 1L CVD T'-MoTe2 exhibits sharp and robust intrinsic Raman bands, with intensities about one order of magnitude stronger than those from bulk T'-MoTe2. The high-quality samples enabled us to reveal the set of all nine even-parity zone-center optical phonons, providing reliable fingerprints for the previously elusive crystal. By performing light polarization and crystal orientation resolved scattering analysis, we can effectively distinguish the intrinsic modes from Te-metalloid-like modes A (~122 cm-1) and B (~141 cm-1) which are related to the sample degradation. Our studies offer a powerful non-destructive method for assessing sample quality and for monitoring sample degradation in situ, representing a solid advance in understanding the fundamental properties of 1L-T'-TMDCs.

References in corpus (4)

• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Toward Air-Stable Multilayer Phosphorene Thin-Films and Transistors
• Environmental Instability and Degradation of Single- and Few-Layer WTe2 Nanosheets in Ambient Conditions
• Activation of new Raman modes by inversion symmetry breaking in type II Weyl semimetal candidate T'-MoTe2

Cited by in corpus (3)

• Structural Phase Transition and Interlayer Coupling in Few-Layer 1T' and Td MoTe2
• Superior valley polarization and coherence of 2s excitons in monolayer WSe2
• Efficient method for calculating Raman spectra of solids with impurities and alloys and its application to two-dimensional transition metal dichalcogenides