  Searching for novel two-dimensional (2D) materials is crucial for the
development of the next generation technologies such as electronics,
optoelectronics, electrochemistry and biomedicine. In this work, we designed a
series of 2D materials based on endohedral fullerenes, and revealed that many
of them integrate different functions in a single system, such as
ferroelectricity with large electric dipole moments, multiple magnetic phases
with both strong magnetic anisotropy and high Curie temperature, quantum spin
Hall effect or quantum anomalous Hall effect with robust topologically
protected edge states. We further proposed a new style topological field-effect
transistor. These findings provide a strategy of using fullerenes as building
blocks for the synthesis of novel 2D materials which can be easily controlled
with a local electric field.
