# Filling-Factor-Dependent Magnetophonon Resonance in Graphene

## TL;DR

This paper investigates a unique fine structure in graphene's optical phonon caused by magnetophonon resonance at high magnetic fields, revealing insights into electron-phonon interactions and filling-factor effects.

## Contribution

It reports the filling-factor-dependent magnetophonon resonance in graphene and demonstrates its potential for measuring electron-phonon coupling and detecting polarized lattice modes.

## Key findings

- Resonance occurs at B_0 ~ 30 T for specific inter-Landau-level transitions.
- The effect allows direct measurement of electron-phonon coupling strength.
- Filling-factor dependence enables detection of circularly polarized lattice modes.

## Abstract

We describe a peculiar fine structure acquired by the in-plane optical phonon at the Gamma-point in graphene when it is brought into resonance with one of the inter-Landau-level transitions in this material. The effect is most pronounced when this lattice mode (associated with the G-band in graphene Raman spectrum) is in resonance with inter-Landau-level transitions 0 -> (+,1) and (-,1) -> 0, at a magnetic field B_0 ~ 30 T. It can be used to measure the strength of the electron-phonon coupling directly, and its filling-factor dependence can be used experimentally to detect circularly polarized lattice modes.