Heat capacity of plutonium nitride at low temperatures

A Hybrid Density Functional Study on PuN

“…It is similar to the case in our previous LSDA studies, indicating that the inclusion of SOC cannot alter the magnetic ordering of PuN. The results from the LSDA+U+SOC and Fock-0.25+SOC schemes illustrate that the PuN is AFM, which is consistent with our previous NSOC calculations and experimental result [8]. Comparing the results obtained at the SOC ( Table V) and NSOC (Table I) levels, we observe the same trend that the lattice constant is slightly increased from NSOC to SOC calculations.…”

“…From the values of energy difference ∆E between the FM and AFM phases given in Table I, we can see that the total energies of the FM phase are lower in the DFT (LSDA/PBE) method. This indicates that the FM state is more stable than the AFM state in the DFT (LSDA/PBE) method, which is not consistent with the available experimental result [8]. On the other hand, DFT+U (LSDA+U/PBE+U) and hybrid DFT (Fock-0.25/PBE0) predict PuN to be AFM, in agreement with experiment.…”

“…The occupied Wyckoff positions are 4a of Pu and 4b of N. The known experimental lattice constant of PuN is 4.905 Å [6]. AFM ordering at 1 K is found in experiment [8]. From the values of energy difference ∆E between the FM and AFM phases given in Table I, we can see that the total energies of the FM phase are lower in the DFT (LSDA/PBE) method.…”

“…In theory, Fynn and Ray [10] investigated the structural, electronic, and magnetic properties of PuN using the full-potential all-electron linearized augmented plane wave (FP-LAPW) plus local orbital method. Their calculations indicated that the ground state of PuN is ferromagnetic, which is contrary to Martin et al [8] conclusion. The ground-state electronic structure of PuN was * corresponding author; e-mail: tangbinre@126.com studied by Petit et al [11] by using the self-interaction corrected local spin-density approximation.…”

“…Some experimental data on structural parameters [6] and thermodynamic properties [7] can be obtained. Antiferromagnetic ordering at 13 K was suggested by Martin et al [8] on the basis of a maximum in magnetic susceptibility and specific heat. A photoelectron spectroscopy experiment on PuN was performed by Havela et al [9].…”