2D Team @ THEOS


Nicola Marzari (EPFL)
Giovanni Pizzi (EPFL)
Rivano Norma (EPFL)
Chiara Cignarella (EPFL)
Fatemeh Haddadi (EPFL)

Former members

Antimo Marrazzo (now at University of Trieste)
Davide Campi (not at University of Milano-Bicocca)
Nicolas Mounet (now at CERN)
Marco Gibertini (now at University of Modena and Reggio Emilia)
Thibault Sohier (now at nanomat/QMAT/CESAM, Université de Liège, Belgium)
Master students: Rong Zhang (visiting from NTU Singapore)


  • Search for novel 2D materials: Two-dimensional materials have emerged as promising candidates for next-generation electronic and optoelectronic applications. Yet, only a few dozens of them have been successfully synthesised. Starting from 108423 unique, experimentally known three-dimensional compounds, we searched for novel 2D materials that can be easily exfoliated from the bulk, identifying 5619 of them according to robust geometric and bonding criteria. High-throughput calculations using van-der-Waals density-functional theory, allow to screen further and identify 1825 compounds that are either easily or potentially exfoliable. For a subset of 258 compounds we have explored vibrational, electronic, and magnetic properties, identifying 56 ferromagnetic and antiferromagnetic systems, including half-metals and half-semiconductors [1,2].
  • Topological materials: we use first-principles atomistic simulations to discover and study novel 2D materials with topological order. We have completed [11] a computational screening of our 2D materials database [1] looking for novel quantum spin Hall insulators (QSHI). In the process, we discovered [3] a novel QSHI in a naturally-occuring mineral that has a large band gap and posses a unique mechanism for electrical switching, thanks to a strong interplay between spin-orbit coupling, inversion crystal-symmetry breaking and dielectric response. See also our news story.
  • Electric transport in 2D materials: Many prospective applications of 2D materials, from transistors to sensors, involve the transport of electrons across the devices. To engineer the best possible devices, one first needs to find the best materials to transport electrons. After identifying hundreds of exfoliable materials, we thus look for those that would lead to the best electronic performances. We simulate the electron-phonon interactions for 2D materials in realistic field-effect setup conditions using a novel implementation of density perturbation theory for gated 2D systems [4]. This code is coupled with the automation power and flexibility of AiiDA to compute the electron-phonon interactions on fine grids. We then solve the Boltzmann transport equation to obtain the phonon-limited transport properties (conductivity, resistivity) with very few approximations.
  • Polar discontinuities in 2D materials: Unprecedented and fascinating phenomena have been observed at oxide interfaces between centrosymmetric cubic materials, where polar discontinuities can give rise to polarization charges and electric fields that drive a metal-insulator transition and the appearance of a two-dimensional electron gas. Lower dimensional analogues are possible and we have shown that polar discontinuities are a widespread and universal phenomenon in 2D, with the emergence of one-dimensional wires of free electrons and holes along the interfaces. In particular, we have identified by extensive first-principles calculations different realistic pathways to engineer polari discontinuities in 2D materials and devices, which are based on: (i) nanoribbons [6,7], where a polar discontinuity against the vacuum emerges; (ii) functionalizations [6], where covalent ligands are used to introduce polar discontinuities by selective or total functionalization of the parent systems; and (iii) structural interfaces, including inversion domain boundaries [7], phase-engineered interfaces and strain profiles [8]. All the cases have the potential to deliver innovative applications in ultra-thin and flexible solar-energy devices and in micro- and nano-electronics.


  • 13/03/2020 Our new article [14] on the emergent dual topology of 3D jacutingaite was published today on Physical Review Research, as an editor's suggestion!
  • 13/03/2020 The joint article [12] resulting from our collaboration with experimental groups on the electronic and topological properties of 3D jacutingaite has was published today in Physical Review Letters!
  • 28/10/2019: Our article [11] on the computational screening for quantum spin Hall insulators was published today in Nano Letters!
  • 14/05/2019: Studying transport in 2D materials, we came up with new ways to engineer their properties and enhance their mobilities as discussed in our article published today on Nano Letters!
  • 29/11/2018: Our work [10] on mobilities was published today in Physical Review Materials, as an editor's suggestion!
  • 13/03/2018: Our new article [3] on the prediction of a novel quantum spin Hall insulator was published today on Physical Review Letters!