Nanoimaging of plasmonic features of WTe2 and twisted-WTe2 at cryogenic temperatures and high-magnetic fields

• Grant number: 25/00060-0
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: June 02, 2025
• End date: June 01, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Raul de Oliveira Freitas
• Grantee: Flávio Henrique Feres
• Supervisor: Mengkun Liu
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil
• Institution abroad: Stony Brook University (SB), United States
• Associated to the scholarship: 23/09839-5 - Natural topological transitions and Luttinger-liquid plasmons in two-dimensional WTe2 crystals in the Terahertz range, BP.PD

Abstract

Recent advancements in the study of plasmonic phenomena in the near-field zone have leveraged graphene-based platforms to explore fundamental near-field optics under extreme environmental conditions. Notable breakthroughs include the first observation of Dirac magnetoexcitons, where an hBN/Gr/hBN device subjected to magnetic fields up to 6 T revealed Dirac magnetoexciton formation at the maximum field intensity. Inspired by these findings, this project aims to investigate similar plasmonic phenomena in tungsten ditelluride (WTe¿), a promising 2D platform with surface plasmon polariton (SPP) activity spanning from the mid-infrared (MIR) to terahertz (THz) ranges. As a type-II Weyl semimetal, WTe¿ exhibits in-plane anisotropy in its dielectric function, enabling topological transitions of SPPs in the far-infrared regime. Recent studies have shown temperature-dependent THz near-field responses in WTe¿ monolayers and multilayers, with metallic behavior observed in thicker layers. This project seeks to further these investigations by exploring the magnetic field dependence of SPPs in WTe¿ at cryogenic temperatures (T < 10 K), where enhanced SPP quality factors are anticipated.