Band structure and infrared optical transitions in ErN

McKay, M. A.; Wang, Q. W.; Al-Atabi, Hayder A.; Yan, Y. Q.; Li, J.; Edgar, James H.; Lin, J. Y.; Jiang, H. X.

doi:10.1063/5.0006312

Cited by 5 publications

(1 citation statement)

References 37 publications

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“…[1][2][3] Due to the presence of partially filled and highly localized 4f orbitals, RENs are ferromagnetic and explored extensively for spin superlattices and spintronic devices. [4,5] The inclusion of rare-earth elements in nonmagnetic semiconductors can also add spin degrees of freedom that lead to their dilute magnetic semiconducting properties for spin-based information processing. [6,7] Erbium nitride (ErN) is one of the most promising REN and is intensely studied to harness its riveting properties in device applications.…”

Section: Introductionmentioning

confidence: 99%

Vibrational Spectrum and Thermal Conductivity of Rare‐Earth Semiconducting Erbium Nitride Thin Films

Upadhya

Kumar

et al. 2022

Physica Rapid Research Ltrs

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Rare‐earth semiconducting mononitrides (RENs) are an emerging class of materials due to their unique electronic and magnetic properties originating from strongly localized 4f orbitals. Erbium nitride (ErN) is one of the most promising REN and attracts significant interest for spintronics, thermoelectric, and Gifford–McMahon cryo‐cooler applications. However, despite such progress, growth and characterization of the physical properties of ErN are rather challenging due to its propensity for oxidation, and no report on its thermal transport properties exists to date. Recently, high‐quality ErN thin films are deposited and are stabilized in ambient with thin capping layers. Herein this letter, first‐principles density functional perturbation theory to model the vibrational spectrum of ErN is utilized and the calculations with the phonon frequency measurements with inelastic Raman spectroscopy are verified. Consistent with its polar dielectric nature, ErN exhibits a longitudinal‐optical transverse‐optical phonon mode splitting at the Γ‐point with a separation of 333 cm−1. Time‐domain thermoreflectance is used to measure the low‐temperature (80 –300 K) thermal conductivity of ErN films. At room temperature, ErN films exhibit a low thermal conductivity of 1.16 ± 0.15 and 2 ± 0.2 W mK−1 on (001) MgO and (0001) Al2O3 substrates, respectively, making them attractive for thermoelectrics and thermal barrier coating applications.

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Section: Introductionmentioning

confidence: 99%

Vibrational Spectrum and Thermal Conductivity of Rare‐Earth Semiconducting Erbium Nitride Thin Films

Upadhya

Kumar

et al. 2022

Physica Rapid Research Ltrs

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Indications of a ferromagnetic quantum critical point in $$\textrm{SmN}_{1-\delta }$$

Holmes-Hewett,

Van Koughnet,

Miller

et al. 2023

Sci Rep

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We investigate the previously observed superconductivity in ferromagnetic SmN in the context of the breakdown of order between two magnetic phases. Nitrogen vacancy doped SmN$$_{1-\delta }$$ 1 - δ is a semiconductor which lies in the intermediary between ferromagnetic SmN and anti-ferromagnetic Sm. Optical data reported here corroborate the prediction that electrical transport is mediated by Sm 4f defect states, and electrical transport measurements characterise the metal-insulator transition over the doping range. Our measurements show that the superconducting state in nitrogen vacancy doped $$\textrm{SmN}_{1-\delta }$$ SmN 1 - δ is the most robust near the breakdown of magnetic order, and indicate the location of a quantum critical point. Furthermore we provide additional evidence that the superconducting state is formed from majority spin electrons and thus of unconventional S = 1 type.

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High thermoelectric power factor in ambient-stable semiconducting rare-earth ErN thin films

Upadhya

Bhatia

Pillai

et al. 2021

Applied Physics Letters

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Erbium nitride (ErN) is an emerging semiconducting rare-earth pnictide with unique electronic and magnetic properties. ErN has attracted significant interest for spin superlattices and spintronic devices and as a second-stage regenerator for Gifford–McMahon cryo-coolers. Solid-solution alloys of ErN with III-nitride semiconductors such as GaN have been studied extensively for use in solid-state lasers, amplifiers, and light-emitting devices operating in the retina-safe and fiber-optic communication wavelength window of 1.54 μm. However, due to the high affinity of Er toward oxygen, ErN is prone to oxidation in ambient conditions. To date, no reports on the deposition of the high-quality ErN thin film and its thermoelectric properties have been published. In this Letter, semiconducting ErN thin films are deposited inside an ultrahigh-vacuum chamber and capped with thin (3 nm) AlN layers to stabilize it in ambient conditions. Structural, optical, and electronic characterization reveals that ErN thin films (a) grow with (111) and (002) orientations on (0001) Al2O3 and (001) MgO substrates with sharp and abrupt ErN–substrate interfaces, (b) demonstrate a direct bandgap of 1.9 eV, and (c) exhibit a high carrier concentration in the range of 4.3 × 1020 to 1.4 × 1021 cm−3. Thermoelectric measurements show a moderately high Seebeck coefficient of –72.6 μV/K at 640 K and a maximum power factor of 0.44 × 10−3 W/m K2 at 486 K. Demonstration of an ambient-stable semiconducting ErN thin film and its high thermoelectric power factor marks significant progress in rare-earth pnictide research and will help develop ErN-based spintronic and thermoelectric devices.

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Band structure and infrared optical transitions in ErN

Cited by 5 publications

References 37 publications

Vibrational Spectrum and Thermal Conductivity of Rare‐Earth Semiconducting Erbium Nitride Thin Films

Vibrational Spectrum and Thermal Conductivity of Rare‐Earth Semiconducting Erbium Nitride Thin Films

Indications of a ferromagnetic quantum critical point in $$\textrm{SmN}_{1-\delta }$$

High thermoelectric power factor in ambient-stable semiconducting rare-earth ErN thin films

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