Due to atomic thinness, van der Waals gaps and high surface area, two-dimensional materials come with unique properties departing from their associated bulk. Those qualities have been found to be controllable by surface modification, which is needed due to the sensitivity for defects and degradation. 2D Black Phosphorus is a promising candidate for electronic and optical devices but lacks stability at ambient conditions.
Here, the chemical functionalization of 2D Black Phosphorus using chiral amino acids is considered within density functional theory. It is shown, that the adsorption of molecules is thermodynamically favored and leads to broken bonds between Phosphorus atoms. Thereby, unpaired electrons in the substrate yield localized in-gap states, which are the source of the perturbed electronic and magnetic structure. The decoration consolidates magnetic order to the nonmagnetic pristine Black Phosphorus sheet. This is only stabilized for homochiral functionalization, i.e. choosing linker molecules with the same chirality. Applying an external perpendicular electric field, the altered monolayer undergoes a semiconductor-halfmetal transition characterized by nonzero conductivity for one spin channel.
The work demonstrates a feasible method, which may be used in chiral anorganic materials to combine properties of Black Phosphorus and chiral molecules. It establishes a basis for further investigation of the enantioselective magnetism. Moreover, the intrinsic magnetic and halfmetallic behavior suggest applications in spintronics.
Lukas obtained his B. Sc. in physics at MLU Halle-Wittenberg. His bachelor thesis was about semiclassical transport theory in Weyl semimetals. Since 2019, he is studying physics at TU Dresden. Lukas joined the group of Prof. Cuniberti for his master thesis under the supervision of Dr. Rafael Gutierrez. He is working on electronic and spin selective properties of functionalized phosphorene using density functional theory based calculations.
Due to atomic thinness, van der Waals gaps and high surface area, two-dimensional materials come with unique properties departing from their associated bulk. Those qualities have been found to be controllable by surface modification, which is needed due to the sensitivity for defects and degradation. 2D Black Phosphorus is a promising candidate for electronic and optical devices but lacks stability at ambient conditions.
Here, the chemical functionalization of 2D Black Phosphorus using chiral amino acids is considered within density functional theory. It is shown, that the adsorption of molecules is thermodynamically favored and leads to broken bonds between Phosphorus atoms. Thereby, unpaired electrons in the substrate yield localized in-gap states, which are the source of the perturbed electronic and magnetic structure. The decoration consolidates magnetic order to the nonmagnetic pristine Black Phosphorus sheet. This is only stabilized for homochiral functionalization, i.e. choosing linker molecules with the same chirality. Applying an external perpendicular electric field, the altered monolayer undergoes a semiconductor-halfmetal transition characterized by nonzero conductivity for one spin channel.
The work demonstrates a feasible method, which may be used in chiral anorganic materials to combine properties of Black Phosphorus and chiral molecules. It establishes a basis for further investigation of the enantioselective magnetism. Moreover, the intrinsic magnetic and halfmetallic behavior suggest applications in spintronics.
Lukas obtained his B. Sc. in physics at MLU Halle-Wittenberg. His bachelor thesis was about semiclassical transport theory in Weyl semimetals. Since 2019, he is studying physics at TU Dresden. Lukas joined the group of Prof. Cuniberti for his master thesis under the supervision of Dr. Rafael Gutierrez. He is working on electronic and spin selective properties of functionalized phosphorene using density functional theory based calculations.
