Cu-Atom Locations in Rocksalt SnTe Thermoelectric Alloy.

The development of functional thermoelectric materials requires direct evidence of dopants' locations to rationally design the electronic and phononic structure of the host matrix. In this study, Cs-corrected scanning transmission electron microscopy and energy dispersive X-ray spectroscopy is employed at the atomic scale to identify Cu atoms' locations in a Cu-doped SnTe thermoelectric alloy. It is revealed that Cu atoms in the rocksalt SnTe form solid solutions at both Sn and Te sites, contrary to their electronegativity order and the intentional Cu doping at Sn sites.

Atomic-Scale Behavior of Perovskite-Supported Ir-Pd-Ru Nanoparticles under Redox Atmospheres.

An advanced materials solution utilizing the concept of "smart catalysts" could be a game changer for today's automotive emission control technology, enabling the efficient use of precious metals via their two-way switching between metallic nanoparticle forms and ionic states in the host perovskite lattice as a result of the cyclical oxidizing/reducing atmospheres. However, direct evidence for such processes remains scarce; therefore, the underlying mechanism has been an unsettled debate. Here, we use advanced scanning transmission electron microscopy to reveal the atomic-scale behaviors for a LaFePdO-supported Ir-Pd-Ru nanocatalyst under fluctuating redox conditions, thereby proving the reversible dissolution/exsolution for Ir and Ru but with a limited occurrence for Pd.

Understanding Micro and Atomic Structures of Secondary Phases in Cu-Doped SnTe.

Highly efficient thermoelectric materials require, including point defects within the host matrix, secondary phases generating positive effects on lowering lattice thermal conductivity (κ ). Amongst effective dopants for a functional thermoelectric material, SnTe, Cu doping realizes the ultra-low κ approaching the SnTe amorphous limit. Such effective κ reduction is first attributed to strong phonon scattering by substitutional Cu atoms at Sn sites and interstitial defects in the host SnTe.

Effects of Ni and Cu Antisite Substitution on the Phase Stability of CuGa from Liquid Ga/Cu-Ni Interfacial Reaction.

Ga and Ga-based alloys have received significant attention for applications in the liquid state and also for their potential as a bonding material in microelectronic assemblies. This study investigates the phase stability of the CuGa phase as a product of the interfacial reaction between liquid Ga and Cu-10Ni substrates at room temperature. In the binary Ga-Cu system, CuGa is decomposed into liquid Ga and CuGa as the temperature increases to around 260 °C, which prevents the widespread application of this alloy.