Discovery of 'Yusaspeun Semiconductor' in Heukrin

Crystal structure of black phosphorus where anisotropic spin semiconductors were discovered

[Asia Economy Reporter Hwang Junho] Domestic researchers have discovered a new type of semiconductor in the black-colored new material 'black phosphorus' (Heukrin). The research team expects that the spin-like property of electrons found in black phosphorus will enable the development of next-generation semiconductors.

The National Research Foundation of Korea announced on the 4th that Professor Geunsu Kim's research team at Yonsei University discovered a 'pseudospin semiconductor' in black phosphorus. Pseudospin is a new property of electrons that appears only in materials with two sublattices and has characteristics similar to the electron's spin.

Clue to Pseudospin Semiconductor

Semiconductor Devices Using Pseudo-Spin Alignment and Direction Control

The research team found that when a honeycomb structure of a material is wrinkled in a specific direction, the pseudospins align along the wrinkle direction. Through black phosphorus, where phosphorus atoms are arranged in a wrinkled honeycomb structure, the team measured the pseudospin direction and confirmed that over 95% are aligned in one direction. Notably, this alignment phenomenon is stable even at high temperatures and appears regardless of the thickness of black phosphorus, increasing its applicability.

It was previously known that pseudospins of electrons appear in materials whose constituent atoms are arranged in a honeycomb pattern. However, no material had been found where pseudospins are aligned and controllable.

The research team explained that by utilizing the unique pseudospin property of black phosphorus, more efficient information processing is possible by controlling the pseudospin direction with external electrical signals.

Research on Pseudospintronics

The research team anticipated that next-generation semiconductors could be developed by harnessing the pseudospin phenomenon of black phosphorus. While existing semiconductors transmit and store information by controlling the flow of electrons with external electrical signals, next-generation semiconductors can process information by controlling the direction of pseudospin.

Professor Geunsu Kim stated, "Pseudospin semiconductors are the pseudospin version of magnetic semiconductors," adding, "Considering that the discovery of magnetic semiconductors pioneered the field of spintronics, the discovery of pseudospin semiconductors could lead to a new emerging field of next-generation semiconductor research called 'pseudospintronics.'"