Metastable polymorphic phases in monolayer TaTe2

Abstract

Polymorphic phases and collective phenomena - such as charge density waves (CDWs) - in transition metal dichalcogenides (TMDs) dictate the physical and electronic properties of the material. Most TMDs naturally occur in a single given phase, but the fine-tuning of growth conditions via methods like molecular beam epitaxy (MBE) allows to unlock otherwise inaccessible polymorphic structures. Exploring and understanding the morphological and electronic properties of new phases of TMDs is an essential step to enable their exploitation in technological applications. Here, we use scanning tunneling microscopy to map MBE-grown monolayer TaTe2. We report the first observation of the 1H polymorphic phase, coexisting with the 1T, and demonstrate that their relative coverage can be controlled by adjusting synthesis parameters. Several super-periodic structures, compatible with CDWs, are observed to coexist on the 1T phase. Finally, we provide theoretical insight on the delicate balance between Te...Te and Ta-Ta interactions that dictates the stability of the different phases. Our findings demonstrate that TaTe2 is an ideal platform to investigate competing interactions, and indicate that accurate tuning of growth conditions is key to accessing metastable states in TMDs.

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Cited by in corpus (6)

• Unveiling the orbital-selective electronic band reconstruction through the structural phase transition in TaTe${}_2$
• Femtosecond trimer quench cycled at megahertz rates in the unconventional charge-density wave material $1\text{T’}-{\text{TaTe}}_2$
• Self-doped flat band and spin-triplet superconductivity in monolayer 1T-TaSe${}_{2-x}$Te${}_x$
• Electronic Landscape of Group-5 Transition Metal Ditellurides $M$Te${}_2$ ($M$ = V, Nb, Ta): Multiple Crystal Phases with Local Bonds and Flat Bands
• The rich structural, electronic and bonding landscape of 1$T$-type TaTe${}_2$ single-layers
• Reversal of charge transfer doping on the negative electronic compressibility surface of MoS2