M. Lavagnini

Raman spectra of neutron-irradiated and Al-doped MgB2

We carried out Raman measurements on neutron-irradiated and Al-doped MgB

Alternative route to charge density wave formation in multiband systems

_2

Raman scattering evidence for a cascade evolution of the charge-density-wave collective amplitude mode

samples. The irradiation-induced topological disorder causes an unexpected appearance of high frequency spectral structures, similar to those observed in lightly Al-doped samples. Our results show that disorder-induced violations of the selection rules are responsible for the modification of the Raman spectrum in both irradiated and Al-doped samples. Theoretical calculations of the phonon density of states support this hypothesis, and demonstrate that the high frequency structures arise mostly from contributions at

Evidence for coupling between charge density waves and phonons in two-dimensional rare-earth tritellurides

{\bf q}\not=0

Optical properties of the Ce and La ditelluride charge density wave compounds

of the E

Pressure dependence of the optical properties of the charge-density-wave compound LaTe2

_{2g}

Pressure-induced quenching of the charge-density-wave state in rare-earth tritellurides observed by x-ray diffraction

phonon mode.

Pressure dependence of the optical properties of the charge-density-wave compound La Te 2

Charge and spin density waves, periodic modulations of the electron, and magnetization densities, respectively, are among the most abundant and nontrivial low-temperature ordered phases in condensed matter. The ordering direction is widely believed to result from the Fermi surface topology. However, several recent studies indicate that this common view needs to be supplemented. Here, we show how an enhanced electron–lattice interaction can contribute to or even determine the selection of the ordering vector in the model charge density wave system ErTe3. Our joint experimental and theoretical study allows us to establish a relation between the selection rules of the electronic light scattering spectra and the enhanced electron–phonon coupling in the vicinity of band degeneracy points. This alternative proposal for charge density wave formation may be of general relevance for driving phase transitions into other broken-symmetry ground states, particularly in multiband systems, such as the iron-based superconductors.

Pressure dependence of the optical properties of the charge-density-wave compoundLaTe2

The two-dimensional rare-earth tritellurides undergo a unidirectional charge-density-wave (CDW) transition at high temperature and, for the heaviest members of the series, a bidirectional one at low temperature. Raman scattering experiments as a function of temperature on

Pressure dependence of the optical properties of the charge-density-wave compound LaTe

{\text{DyTe}}_{3}