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Rare-earth nitride (REN) pnictides are exciting materials due to their localized and strongly correlated 4f-electrons that lead to interesting magnetic properties useful for spintronic devices. Ytterbium nitride (YbN) is a unique rare-earth pnictide as it exhibits antiferromagnetic ground states, unlike most ferromagnetic RENs. Though the magnetic properties of YbN thin films have been studied before, the electronic, thermoelectric, and plasmonic properties of YbN are yet to be investigated. Here, we show coexisting high thermoelectric power factor and short-wavelength infrared plasmon polaritons in epitaxial YbN thin films deposited with the ultrahigh vacuum growth method. YbN thin films deposited on (001) MgO substrates exhibit epitaxial and good quality crystalline growth and exhibit a high thermoelectric power factor of ∼ 1.9 mW/mK2 at 750 K due to high electrical conductivity and a moderately high Seebeck coefficient. High carrier concentration also leads to a positive-to-negative dielectric permittivity transition in YbN at ∼1900–1950 nm, corresponding to the epsilon-near-zero plasmonic resonance. Low-temperature transport measurements revealed that dislocation and acoustic phonon scattering dominate electronic transport. Demonstration of coexisting high thermoelectric power factor and infrared plasmon polaritons marks important progress in designing YbN-based thermoelectric and plasmonic devices for future applications. [ABSTRACT FROM AUTHOR]

Epitaxial metal/semiconductor multilayers are attractive materials for a range of solid-state energy conversion devices. Applications include waste-heat-to-electrical energy conversion, hot-electron-based solar energy conversion in photocatalysis and photodiodes, optical hyperbolic metamaterials, and engineering thermal hyperconductivity. ZrN/ScN is among the first metal/semiconductor multilayer structures to also display promising thermal and electronic properties. However, for efficient thermionic transport, it is necessary to control and tune the Schottky barrier height at the metal/semiconductor interfaces, since this controls current flows across the superlattices' cross-plane directions. Sputter-deposited semiconducting ScN in ZrN/ScN multilayers contains a high concentration of n-type carriers, primarily due to oxygen impurities. This leads to a very small depletion width at metal/semiconductor interfaces, preventing thermionic transport. To overcome this challenge, the n-type carrier concentration of ScN has been reduced by Mg hole doping to ~ 1.6 × 1018 cm−3. In this article, we report the growth of thermally stable epitaxial ZrN/carrier-compensated Sc0.99Mg0.01N multilayers useful for thermionic emission-based devices. We present carrier concentration and transport regime calculations. Characterization of the microstructure and thermal stability was performed by combining aberration-corrected scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy mapping, and atom probe tomography. The results show stoichiometric Sc0.99Mg0.01N layers with a uniform magnesium concentration, and lattice-matched ZrN/Sc0.99Mg0.01N growth with smooth and atomically sharp interfaces that are thermally stable after 48 h at 950º C. The successful demonstration of thermally stable ZrN/carrier-compensated Sc0.99Mg0.01N multilayers with a semiconductor carrier concentration of 2 × 1018 cm−3 is expected to enable efficient thermionic transport devices with improved properties. [ABSTRACT FROM AUTHOR]