title: Effect of the spin-orbit interaction on the thermodynamic properties of crystals: specific heat of bismuth.
abstract: We discuss measurements and ab initio calculations of the specific heat for crystalline bismuth, strictly speaking, a semimetal but in the temperature region accessible to us (T>2 K) acting as a semiconductor. We extend experimental data available in the literature and notice that the ab initio calculations without spin-orbit interaction exhibit a maximum at approximately 8 K, about 20% lower than the measured one. Inclusion of spin-orbit interaction decreases the discrepancy markedly: the maximum of C(T) is now only 7% larger than the measured one. Exact agreement is obtained if the strength of the spin-orbit Hamiltonian is reduced by a factor of approximately 0.9. We also discuss the dependence of the lattice parameter and the cohesive energy on spin-orbit interaction.
authors.affiliation: CINVESTAV-Querétaro, Libramiento Norponiente 2000, Fraccionamiento Real de Juriquilla 76230 Querétaro, Querétaro Mexico.
authors.forename: L E
authors.initials: LE
authors.lastname: Díaz-Sánchez
authors.forename: A H
authors.initials: AH
authors.lastname: Romero
authors.forename: M
authors.initials: M
authors.lastname: Cardona
authors.forename: R K
authors.initials: RK
authors.lastname: Kremer
authors.forename: X
authors.initials: X
authors.lastname: Gonze