We are a theoretical and computational condensed-matter theory group at DISMI, University of Modena and Reggio Emilia. We work on how electrons and atomic vibrations interact in materials, and on turning that interaction into numbers you can compare with an experiment — scattering rates, mobilities, linewidths, spectra.

"What I cannot create, I do not understand"

Electron–phonon coupling beyond mean field

The standard way to compute electron–phonon coupling treats the electronic response at mean-field level, ignoring the attraction between the electron and the hole that a vibrating lattice creates. In weakly screened materials this is not a small omission. We derive electron–phonon vertices that include these electron–hole correlations, and we insist that the same vertex govern both how a phonon decays and how an electron scatters — otherwise the two rates violate detailed balance. In graphene the correction to zone-boundary coupling is large: a factor of a few in the linewidths.

Selected work
— Guandalini, Caldarelli, Macheda, Mauri, Phys. Rev. Lett. 135, 076401 (2025)
— Caldarelli, Guandalini, Macheda, Mauri, Phys. Rev. B 111, 075137 (2025)
— Guandalini, Caldarelli, Mauri, Macheda, The principle of detailed balance between electrons and phonons in presence of excitonic effects (2026, to be submitted)

Screening and long-range potentials in two dimensions

In a two-dimensional crystal the electric fields produced by vibrating atoms leak out of the material, so the surrounding environment becomes part of the problem. Free carriers screen those fields dynamically; an encapsulating dielectric screens some interactions while adding vibrations of its own. We build the electrostatics and the screening of phonons in doped and encapsulated 2D systems, including the remote phonons of the substrate. Methodologically, we start from first-principles linear response calculations for isolated monolayers, and build the dielectric matrix of a full heterostructure solving mean field equations. Its resonances give the electrodynamical excitations and their coupling to electrons.

Selected work
— Macheda, Sohier, Barone, Mauri, Phys. Rev. B 107, 094308 (2023)
— Macheda, Sohier, arXiv:2604.01746 (2026)
— Dinar et al., arXiv:2604.00678 (2026)

Richard Feynman

Transport, from scattering rates to measured currents

A scattering rate is not a mobility. Getting from one to the other means solving the Boltzmann equation properly, keeping track of which collisions actually relax the current, and being careful about what the experiment measures — a Hall mobility is not a drift mobility. We work on coupled electron and phonon transport where both subsystems are treated on the same footing.

Selected work
— Macheda, Poncé, Giustino, Bonini, Nano Lett. 20, 8861 (2020)
— Macheda, Sohier, arXiv:2604.01746 (2026)

— Dinar et al., arXiv:2604.00678 (2026)

Spectroscopy as the testing ground

Theories of electron–phonon coupling are cheap to propose and hard to falsify, so we test ours against spectroscopy. Raman scattering probes the coupling locally in momentum space; resistivity probes its integrated effect; photoemission linewidths probe the electronic side of the same process. We collaborate closely with experimental groups, which is the only way this works.

Selected work
— Venanzi et al., Phys. Rev. Lett. 130, 256901 (2023)
— Graziotto et al. , Nano Letters 24 (6): 1867–1873 (2024)