Layer-dependent Raman spectroscopy of ultrathin Ta${}_2$Pd${}_3$Te${}_5$

Abstract

Two-dimensional topological insulators (2DTIs) or quantum spin Hall insulators are attracting increasing attention due to their potential applications in next-generation spintronic devices. Despite their promising prospects, realizable 2DTIs are still limited. Recently, Ta2Pd3Te5, a semiconducting van der Waals material, has shown spectroscopic evidence of quantum spin Hall states. However, achieving controlled preparation of few- to monolayer samples, a crucial step in realizing quantum spin Hall devices, has not yet been achieved. In this work, we fabricated few- to monolayer Ta${}_2$Pd${}_3$Te${}_5$ and performed systematic thickness- and temperature-dependent Raman spectroscopy measurements. Our results demonstrate that Raman spectra can provide valuable information to determine the thickness of Ta2Pd3Te5 thin flakes. Moreover, our angle-resolved polarized Raman (ARPR) spectroscopy measurements show that the intensities of the Raman peaks are strongly anisotropic due to the quasi-one-dimensional atomic structure, providing a straightforward method to determine its crystalline orientation. Our findings may stimulate further efforts to realize quantum devices based on few or monolayer Ta${}_2$Pd${}_3$Te${}_5$.

References in corpus (9)

• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Anomalous Lattice Vibrations of Single and Few-Layer MoS2
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Making graphene visible
• Observation of the Quantum Spin Hall Effect up to 100 Kelvin in a Monolayer Crystal
• Interference enhancement of Raman signal of graphene
• Quadrupole topological insulators in Ta2M3Te5 (M= Ni, Pd) monolayers
• Anharmonicity in Raman-active phonon modes in atomically thin MoS${}_2$
• Quantum Spin Hall Effect in Ta${}_2$M${}_3$Te${}_5$ (M = Pd, Ni)

Cited by in corpus (1)

• Realization of Air-Stable Two-Dimensional Superconductor Nb2Pd3Te5 With Quasi-One-Dimensional Pair Density Modulation