Properties of Rare-Earth Nitrides

Abstract

The optical and electrical properties of the rare-earth nitrides DyN, ErN, and HoN as well as ScN and YN have been surveyed. From absorption edges found in the optical transmission curves, energy gaps in the 2-eV range were determined as follows: DyN 2.60–2.90 eV, ErN 2.40–2.78 eV, HoN 1.70–1.88 eV, where the spread in energies is due to differences observed in two experimental runs. For ScN and YN no definite absorption edge was found. The electrical properties from 80° up to 1500°K were found to be metallic with associated large concentrations of electron carriers. These results are interpreted to suggest that the present species of nitrides which were all deficient in nitrogen content are high energy gap defect type degenerate semiconductors. The large concentrations of charge carriers are attributed to the lack of stoichiometry so far achieved.

Magnetic properties of ErN films

“…The first experimental data obtained on ErN evidenced the complexity of the problem due to a lack of stoichiometry. Early reports [15] suggest an optical gap near 2 eV, together with a resistivity of the order of 100 mOcm at room temperature, which shows a metallic behavior with a large concentration of electron carriers, attributed to nitrogen vacancies. This behavior was in fact found for most of the RN in those early studies.…”

Optical response of DyN

“…There are decades-old reports 18,19 of absorption edges of almost all RENs, with the exception of CeN and PmN, though it is now recognised that those early materials were subject to the formation of nitrogen vacancies and decomposition as oxides in air. In particular DyN has been reported to show an onset of absorption ranging 18-20 from 2.9 eV to 0.91 eV.…”

Semiconductor of spinons: from Ising band insulator to orthogonal band insulator

“…Within this scenario, once a system is found in IBI phase, simply rising the temperature gives a chance to the OBI phase. If the anomalous magnetic field dependence of the transport properties in monochalcogenides [39,40] is due to the Ising order, then searching for "ARPES-dark" states in elevated temperature can support this assumption. By increasing the temperature, once the underlying Ising order is lost, the ARPES gaps starts to deviate from thermal gap.…”

“…This may provide extra sensitivity to B field in Ising semiconductors as opposed to normal semiconductors. Given that the resistivity of rare earth monochalcogenides is very sensitive to applied magnetic fields, and that the heavy Fermion elements involved are qualified for strong correlations, we suspect that rare earth semiconducting systems such as Europium monochalcogenides EuX or Samarium monochalcogenides SmX where X=S, Se, Te [39] and rare earth nitrides [40] can be interesting platforms to search for signatures of underlying Ising condensate.…”

“…This may provide extra sensitivity to B field in Ising semiconductors as opposed to normal semiconductors. Given that the resistivity of rare earth monochalcogenides is very sensitive to applied magnetic fields, and that the heavy Fermion elements involved are qualified for strong correlations, we suspect that rare earth semiconducting systems such as Europium monochalcogenides EuX or Samarium monochalcogenides SmX where X=S, Se, Te [39] and rare earth nitrides [40] can be interesting platforms to search for signatures of underlying Ising condensate.Let us briefly discuss the connection of the present work to other works on the ionic Hubbard model. Investigations of the nature of intermediate phase in the ionic Hubbard model fall into two major groups: First group suggests that the intermediate phase is gapped, while the second group suggests gapless intermediate state.…”