Orkestra Rumpilezz

Chapter 3 presents the book’s first case study, Orkestra Rumpilezz, a big band mixing jazz with emblematic Afro-Bahian genres such as Candomblé, carnival music (ijexá and samba reggae), samba de roda, and capoeira. It opens with a discussion of composer-director Letieres Leite’s trajectory in Brazil and Europe and his views on Africa and the liminal status of jazz in Bahia, as an African diasporic genre and, simultaneously, US America’s classical music. This is followed by an analysis of how the orchestra spotlights percussion and percussionists in its performances and links them to the polemic notion of racial democracy in Brazil. A number of performance practices (layout of musicians on stage, colors and styles of costumes, visual symbols, instrumentation, physical movement, speech between pieces) are connected with the tropes of embodiment, spirituality, and spontaneity.

Ge1−xSnx alloys: Consequences of band mixing effects for the evolution of the band gap Γ-character with Sn concentration

In this work we study the nature of the band gap in GeSn alloys for use in silicon-based lasers. Special attention is paid to Sn-induced band mixing effects. We demonstrate from both experiment and ab-initio theory that the (direct) Γ-character of the GeSn band gap changes continuously with alloy composition and has significant Γ-character even at low (6%) Sn concentrations. The evolution of the Γ-character is due to Sn-induced conduction band mixing effects, in contrast to the sharp indirect-to-direct band gap transition obtained in conventional alloys such as Al1−xGaxAs. Understanding the band mixing effects is critical not only from a fundamental and basic properties viewpoint but also for designing photonic devices with enhanced capabilities utilizing GeSn and related material systems.

Valence Band Mixing in GaAs/AlGaAs Quantum Wells Adjacent to Self-Assembled InAlAs Antidots

Optical properties of GaAs/AlGaAs quantum wells (QWs) in the vicinity of InAlAs quantum dots (QDs) were studied and compared with a theoretical model to clarify how the QD strain affects the electronic states in the nearby QW. In0.4Al0.6As QDs are embedded at the top of the QWs; the QD layer acts as a source of strain as well as an energy barrier. Photoluminescence excitation (PLE) measurements showed that the QD formation leads to the increase in the ratio Ie-lh/Ie-hh of the PLE intensities for the light hole (lh) and the heavy hole (hh), indicating the presence of the valence band mixing. We also theoretically calculated the hh-lh mixing in the QW due to the nearby QD strain and evaluated the PLE ratio Ie-lh/Ie-hh.