# Anomalies in G and 2D Raman Modes of Twisted Bilayer Graphene Near the Magic Angle

**Authors:** Darshit Solanki, Kenji Watanabe, Takashi Taniguchi, A. K. Sood, Anindya Das  
**arXiv:** [2506.18166](https://arxiv.org/abs/2506.18166)  
**Date:** 2025-06-22  
**Summary page:** https://www.summarizepaper.com/fr/paper/2506.18166v1/

## Abstract

The role of twist angle ($\theta_t$) in tailoring the physical properties of heterostructures is emerging as a new paradigm in two-dimensional materials. The influence of flat electronic bands near the magic angle ($\sim$1.1$^{\circ}$) on the phononic properties of twisted bilayer graphene (t-BLG) is not well understood. In this work, we systematically investigate the G and 2D Raman modes of t-BLG samples with twist angles ranging from $\sim$0.3$^{\circ}$ to $\sim$3$^{\circ}$ using micro-Raman spectroscopy. A key finding of our work is the splitting of the G mode near the magic angle due to moir\'e potential induced phonon hybridization. The linewidth of the low-frequency component of the G mode (G$^-$), as well as the main component of the 2D mode, exhibits enhanced broadening near the magic angle due to increased electron-phonon coupling, driven by the emergence of flat electronic bands. Additionally, temperature-dependent Raman measurements (6-300 K) of magic-angle twisted bilayer graphene sample ($\theta_t \sim$ 1$^{\circ}$) reveal an almost tenfold increase in phonon anharmonicity-induced temperature variation in both components of the split G mode, as compared to Bernal-stacked bilayer graphene sample, further emphasizing the role of phonon hybridization in this system. These studies could be important for understanding the thermal properties of the twisted bilayer graphene systems.