gftool.fcc_dos

gftool.fcc_dos(eps, half_bandwidth)

DOS of non-interacting 3D face-centered cubic lattice.

Has a van Hove singularity at z=-half_bandwidth/2 (divergence) and at z=0 (continuous but not differentiable).

Parameters
epsfloat np.ndarray or float

DOS is evaluated at points eps.

half_bandwidthfloat

Half-bandwidth of the DOS, DOS(eps < -0.5*`half_bandwidth`) = 0, DOS(1.5*`half_bandwidth` < eps) = 0. The half_bandwidth corresponds to the nearest neighbor hopping t=D/8

Returns
dosfloat np.ndarray or float

The value of the DOS.

See also

gftool.lattice.fcc.dos_mp

multi-precision version suitable for integration

References

morita1971

Morita, T., Horiguchi, T., 1971. Calculation of the Lattice Green’s Function for the bcc, fcc, and Rectangular Lattices. Journal of Mathematical Physics 12, 986–992. https://doi.org/10.1063/1.1665693

Examples

>>> eps = np.linspace(-1.6, 1.6, num=501)
>>> dos = gt.lattice.fcc.dos(eps, half_bandwidth=1)
>>> import matplotlib.pyplot as plt
>>> _ = plt.axvline(0, color='black', linewidth=0.8)
>>> _ = plt.axvline(-0.5, color='black', linewidth=0.8)
>>> _ = plt.plot(eps, dos)
>>> _ = plt.xlabel(r"$\epsilon/D$")
>>> _ = plt.ylabel(r"DOS * $D$")
>>> _ = plt.ylim(bottom=0)
>>> _ = plt.xlim(left=eps.min(), right=eps.max())
>>> plt.show()

(png, pdf)

../_images/gftool-fcc_dos-1.png