Event calendar file
DCMPMS Seminars
Phase transitions in 2D transition metal dichalcogenides
by Mr. Abhay Shukla ((Sorbonne University))
Thursday, August 10, 2023
from
to
(Asia/Kolkata)
at AG 69
at AG 69
| Description |
Few layer transition metal dichalcogenides are 2D materials extensively studied for the contrasting electronic and optical properties of their phases and the transitions between them which could be interesting for eventual applications. In this work we take a closer look at temperature and electrostatic doping driven phase transitions in MoTe2 and WTe2. MoTe2 has a stable hexagonal semiconducting phase (2H) as well as two semi metallic phases with monoclinic and orthorhombic structures. A structural transition could thus be accompanied by a significant change in electronic properties. The two semi-metallic phases are connected by a temperature driven transition and could exhibit topological properties. Recent work in MoTe2 has raised the possibility of a hexagonal-monclinic transition through technology compatible pathways, activated by electrostatic gating [1,2]. Here [3] we make extensive Raman measurements of few layer MoTe2 and WTe2 and find that few-layer tellurides are characterized by high mobility of Te ions, even in ambient conditions and especially through the variation of external parameters like electric field or temperature. These can generate Te clusters, vacancies at crystalline sites and facilitate structural transitions. We also find that the purported transition in MoTe2 cannot be obtained by a pure electrostatic field. [1] Wang et al. Nature, 470, 550 (2017) [2] Zakhidov et al. ACS Nano, 2894, 14 (2020) [3] Kowalczyk et al. ACS Nano, 6708, 17 (2023) |
