Investigation of the Electron–Phonon Coupling in Dirac Semimetal PdTe₂ via Temperature‐Dependent Raman Spectroscopy

Abstract

Layered Palladium ditelluride (PdTe2) is an interesting noble‐transition‐metal dichalcogenide with high electrical and thermal conductivity, exhibiting superconductivity and a type‐II Dirac semimetallic phase due to the increased electron–phonon (e–ph) coupling. Herein, the e–ph coupling constant λ of E g (in‐plane) and A 1g (out‐of‐plane) modes in the exfoliated PdTe2 nanoflakes via temperature‐dependent Raman spectroscopy within the temperature range from 80 to 580 K is determined. Both E g mode with a Gaussian line shape and A 1g mode with a Breit–Wigner–Fano line shape show nonlinear frequency redshift and linewidth broadening with temperature. The extracted e–ph coupling constants are λ E g = 1.54 and λ A 1 g = 0.55, respectively. The Raman results confirm that PdTe2 is a phonon‐mediated Bardeen–Cooper–Schrieffer superconductor.

Fully‐Depleted PdTe2/WSe2 van der Waals Field Effect Transistor with High Light On/Off Ratio and Broadband Detection

“…[ 9 ] From the Raman spectrum of PdTe 2 , two main peaks of PdTe 2 can be seen at ≈57 and 137 cm −1 . The stronger peak at 57 cm −1 in response to the E g 1 phonon mode, and the peak at 137 cm −1 corresponds to the A 1g 2 phonon mode [ 7,10 ] (Figure 1d red line). In the heterostructure region of the device, Raman characteristic peaks of WSe 2 and PdTe 2 can be clearly observed, which are consistent with the corresponding reported spectra (Figure 1d black line).…”

“…[ 6 ] For example, as an important type II Dirac semimetal, PdTe 2 has extremely high charge carrier mobility (2735 ± 112 and 2570 ± 234 cm 2 V −1 s −1 in c ‐ and ab ‐axes), high thermal conductivity (≈130 W m −1 K −1 ) and electrical conductivity (≈4.3 × 10 6 S m −1 ), excellent environmental stability and anisotropic in‐plane properties. [ 7 ] What's more, the special energy band structure leads to an adjustable bandgap, so it can be transformed from the behavior of metal in bulk crystal to narrow bandgap semiconductor with single layer thickness. [ 8 ] This provides a platform for fabricating high‐performance broadband photodetectors.…”

Surface properties of 1T-TaS2 and contrasting its electron-phonon coupling with TlBiTe2 from helium atom scattering

“…These results suggest an equal or even more significant λ compared to TIs such as TlBiTe 2 . However, experimental approaches in connection with Weyl materials are mainly based on temperature-dependent Raman studies, thus focusing on optical phonon modes and being rather bulk sensitive ( Xu et al, 2017 ; Choe et al, 2021 ; Osterhoudt et al, 2021 ; Al-Makeen et al, 2022 ). In light of these results, surface-sensitive experimental reports about the average e-ph coupling λ of Weyl semimetals are not available to the best of our knowledge, preventing us from providing a decent comparison with these.…”

Interfacial Effects on the Photoluminescence Properties of Epitaxial Monolayer MoS2 on MoO2 on C‐Sapphire

“…PL and Raman spectra were collected using an inVia Qotor system (Renishaw, UK) with 532 nm excitation and a 1800 lines/mm grating. [ 32 ] The TDPL and temperature‐dependent Raman (TDR) were collected on the nanoflakes with a step of 20 K. [ 33–35 ] All Raman spectra in Figure a and were normalized to the maximum Raman intensities of of MoS 2 and the high‐frequency Mo–O stretching vibration of MoO 2 , respectively. The WSxM, WiRE, and Origin software were used for experimental data analysis.…”