Search

Abstract There is tremendous interest in measuring the strong electron–phonon interactions seen in topological Weyl semimetals. The semimetal NbIrTe4 has been proposed to be a Type-II Weyl semimetal with 8 pairs of opposite Chirality Weyl nodes which are very close to the Fermi energy. We show using polarized angular-resolved micro-Raman scattering at two excitation energies that we can extract the phonon mode dependence of the Raman tensor elements from the shape of the scattering efficiency versus angle. This van der Waals semimetal with broken inversion symmetry and 24 atoms per unit cell has 69 possible phonon modes of which we measure 19 modes with frequencies and symmetries consistent with Density Functional Theory calculations. We show that these tensor elements vary substantially in a small energy range which reflects a strong variation of the electron–phonon coupling for these modes.

The complex band structure and carrier decay response upon photoexcitation of the chiral semiconductor tellurium remain to be unveiled. Here, the authors report unusual dynamic band modifications in Te near band-edge structure due to photoinduced symmetry breaking and strong anisotropy in carrier decay dynamics.

We review a number of time-resolved photoluminescence experiments which have provided new understanding of the physical properties of single nanowires and single semiconductor nanowire heterostructures. Specifically, TRPL spectroscopy has been used to understand more fully non-radiative surface and bulk defects, radiative defects in CdS, InP and GaAs nanowires, core-shell effects, polytypism in InP nanowires, many body effects in GaAs and InP nanowires, and type-II band alignments in ZB/WZ mixed phase nanowires. [ABSTRACT FROM AUTHOR]