Relativistic Effects

Relativistic effects are treated with the accurate and efficient ZORA approach [17, 18], controlled by the Relativistic keyword. Relativistic effects are negligible for light atoms, but grow to dramatic changes for heavy elements. A rule of thumb is: Relativistic effects are quite small for elements of row 4, but very large for row 6 elements (and later).

Relativistic [None|ZORA|ZORA Spin]

This key instructs BAND to take relativistic effects into account. (Default: none)

No relativistic effects
Scalar relativistic ZORA. This option comes at very little cost.
Spin-orbit coupled ZORA. This is the best level of theory, but it is (4-8 times) more expensive than a normal calculation. Spin-orbit effects are generally quite small, unless there are very heavy atoms in your system, especially with p valence electrons (like Pb). See also the SpinOrbitMagnetization key.