  Entanglement generated from polar molecules of two-dimensional rotation is
investigated in a static electric field. The electric field modulates the
rotational properties of molecules, leading to distinctive entanglement. The
concurrence is used to estimate the degree of entanglement. When the electric
field is applied parallel or perpendicular to the intermolecular direction, the
concurrences reveal two overlapping features. Such a pronounced signature
corresponds to the coexistence of all Bell-like states. The characteristics of
Bell-like states and overlapping concurrences are kept independent of the
modulation of dipole-field and dipole-dipole interactions. On the contrary, the
Bell-like states fail to coexist in other field directions, reflecting
nonoverlapping concurrences. Furthermore, the thermal effect on the
entanglement is analyzed for the Bell-like states. Dissimilar suppressed
concurrences occur due to different energy structures for the two specific
field directions.
