Electronic structure, magnetism, and spin-dependent transport of ${\mathrm{CeMnNi}}_4$

Theoretical investigations of the electronic band structure and ferromagnetism of ${\mathrm{CeMnNi}}_4$ have been performed by means of a local spin density approximation approach. The calculated magnetic moment of $4.88{\mu }_B$ per formula unit is in good agreement with the value determined experimentally. Recent point-contact Andreev reflection experiments show that this compound has a relatively large transport spin polarization. The calculations reveal a much smaller polarization of the density of states and transport coefficients at the Fermi level. A shift of the Fermi level by $0.1\mathrm{eV}$ raises the polarization values close to the experimental ones.

Figure 1

(Color online) Crystallographic structures of (a) the hexagonal ${\mathrm{CeNi}}_5$ and (b) the cubic ${\mathrm{CeMnNi}}_4$ compound.

Figure 2

(Color online) Total magnetic moment (black squares) as well as magnetic moments of Ce (open down triangles), Mn (solid circles), and Ni (solid up triangles) as a function of lattice constant of ${\mathrm{CeMnNi}}_4$. The vertical lines mark theoretical and experimental values of the lattice constant, respectively.

Figure 3

(Color online) Total and partial densities of states of the nonmagnetic hexagonal ${\mathrm{CeNi}}_5$.

Figure 4

(Color online) Total spin-dependent DOS of ${\mathrm{CeMnNi}}_4$ and the local DOS for Ce, Mn, and Ni (from top to bottom), respectively.

Figure 5

The spin-resolved band structure of ${\mathrm{CeMnNi}}_4$ over wide energy range (upper panel) and in the vicinity of Fermi level (lower panel). Solid and broken lines represent spin-up and spin-down electronic channels, respectively.

Figure 6

(Color online) Spin-dependent densities of states $N$, Sharvin conductance $\left(Nv\right)$, plasma frequencies $\left(N{v}^2\right)$ (upper panel), and the derived spin polarizations (lower panel) at the theoretical lattice constant of ${\mathrm{CeMnNi}}_4$.

Figure 7

(Color online) Fermi velocity distribution $\mid v_{\mathbf{k}}\mid$ for majority (left) and minority (right) spin states of ${\mathrm{CeMnNi}}_4$ at the theoretical lattice constant (in units of $8.1\times {10}^6,\text{cm}{\sec }^{-1}$).