Physical properties of the cubic spinel LiMn2O4

• The density of states at the Fermi level is dominated by Mn 3d electrons.
• Phonon modes between 250 and 375 cm−1 are characterized by vibrations of all atom types.
• Temperature dependence of entropy which produces the reversible heat is presented.
• The Debye temperature at 300 K is calculated to be 820.80 K.
• The behavior of the heat capacity is in agreement with Debye specific heat theory.

We have performed an ab initio study of structural, electronic, magnetic, vibrational and thermal properties of the cubic spinel LiMn2O4 by employing the density functional theory, the linear-response formalism, and the plane-wave pseudopotential method. An analysis of the electronic structure with the help of electronic density of states shows that the density of states at the Fermi level (N (EF)) is found to be governed by the Mn 3d electrons with some contributions from the 2p states of O atoms. It is important to note that the contribution of Mn 3d states to N(EF)N(EF) is as much as 85%. From our phonon calculations, we have obtained that the main contribution to phonon density of states (below 250 cm−1) comes from the coupled motion of Mn and O atoms while phonon modes between 250 cm−1 and 375 cm−1 are characterized by the vibrations of all the three types of atoms. The contribution from Li increases rapidly at higher frequency (above 375 cm−1) due to the light mass of this atom. Finally, the specific heat and the Debye temperature at 300 K are calculated to be 249.29 J/mol K and 820.80 K respectively.