Highlights
Extending abinitio modelling to vibrational electron energy loss spectroscopy
By combining microscopic density functional theory calculations with the electrostatic formalism necessary to account for the experimental specificities of electron energy loss spectroscopy (EELS) as implemented in the transmission electron microscope, we showed how a quantitative description of the experimental spectra obtained on molecular crystals in the vibrational range of frequencies can be reached.
Reference
"Firstprinciples vibrational electron energy loss spectroscopy of βguanine"
G. Radtke, D. Taverna, M. Lazzeri and E. Balan, PHYSICAL REVIEW LETTERS 119, 027402 (2017)

Probing the quantum thermal fluctuations of nuclei by Xray absorption spectroscopy and Nuclear Magnetic Resonance
In material sciences, local spectroscopies such as Xray absorption (XANES) and solidstate nuclear magnetic resonance (NMR) are commonly interpreted using abinitio calculations performed assuming an equilibrium static lattice. Yet, nuclear motion affects spectra even when reduced to the zeropoint motion at 0 K. For instance, the nuclear dynamics generates specific discrepancies between standard calculations and measurements, such as an additional XAS preedge peak involving forbidden electronic transitions and inaccurate assignment of NMR resonance peaks. We developed a theoretical framework based on DFT that includes quantum thermal fluctuations in the calculation of the XAS crosssection and NMR parameters (chemical shifts, quadrupolar coupling constants), and allows a good description of the temperature effects observed experimentally.
Reference
"Temperature dependence of Xray absorption and nuclear magnetic resonance spectra: probing quantum vibrations of light elements in oxides."
Nemausat R., Gervais C., Brouder C., Trcera N., Bordage A., CoelhoDiogo C., Florian P., Rakhmatullin A., Errea I., Paulatto L., Lazzeri M. and Cabaret D. PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19, 6246–6256 (2017)

Exchange interaction and the chargedensitywave instability in TiSe_{2}
The exchange interaction is due to the exchange symmetry of the wave function of indistinguishable particles, and hence of quantum mechanical origin. In standard abinitio calculations based on local approximations to the exchangecorrelation energy (e.g. LDA and GGA) this interaction is only partially captured. In this work we show that the fully nonlocal description of exchange is needed to capture the physics of TiSe_{2}. The exchange interaction provides two competing effects, a short range repulsive interaction, important for the electronic band structure, and a longrange attractive electronhole interaction which cooperates with the electronphonon interaction to induce the chargedensitywave transition in TiSe_{2}.
Reference
"Critical Role of the Exchange Interaction for the Electronic Structure and ChargeDensityWave Formation in TiSe_{2}"
Hellgren M., Baima J., Bianco R., Calandra M., Mauri F., and Wirtz L., PHYSICAL REVIEW LETTERS 119, 176401 (2017)

Rashba coupling amplification by a staggered crystal field
There has been increasing interest in materials where relativistic effects induce nontrivial spin splittings with promise for spintronics applications. Sizable splittings have been hitherto obtained using heavy elements, where the Rashba spinorbit coupling is intrinsically strong. This paradigm has been broken by our finding of a large Rashba coupling in the BaNiS2, where nickel is spinorbit active, despite its low Z number. This unexpected result in the absence of heavy elements demonstrates an effective mechanism of Rashba coupling amplification that may foster spinorbit band engineering.
Reference
"Rashba coupling amplification by a staggered crystal field"
David SantosCottin, Michele Casula, Gabriel Lantz, Yannick Klein, Luca Petaccia, Patrick Le Fèvre, François Bertran, Evangelos Papalazarou, Marino Marsi & Andrea Gauzzi Nature Communications, 7, 11258 (2016)