Quantum Lifetime Spectroscopy and Magnetotunneling in Double Bilayer Graphene Heterostructures

TL;DR

This paper introduces a tunneling spectroscopy method in double bilayer graphene heterostructures to measure quasiparticle broadening, revealing linear energy dependence and minimal temperature effects, with insights into layer alignment.

Contribution

It presents a novel spectroscopy technique utilizing momentum-conserving tunneling to probe quasiparticle properties in graphene heterostructures.

Findings

Quasiparticle broadening increases linearly with energy.

Broadening shows weak temperature dependence.

High rotational alignment between graphene layers is confirmed.

Abstract

We describe a tunneling spectroscopy technique in a double bilayer graphene heterostructure where momentum-conserving tunneling between different energy bands serves as an energy filter for the tunneling carriers, and allows a measurement of the quasi-particle state broadening at well defined energies. The broadening increases linearly with the excited state energy with respect to the Fermi level, and is weakly dependent on temperature. In-plane magnetotunneling reveals a high degree of rotational alignment between the graphene bilayers, and an absence of momentum randomizing processes.