After exponential rapid development, traditional silicon-based CMOS technology has entered the sub-10 nanometer node, approaching its size and performance limit. In the future, the development of core electronic devices for information technology and industry is an important issue that has received widespread attention.
Traditional silicon-based technology mainly uses the charge characteristics of electrons. Can the spin properties of electrons be used to construct spin transistors, especially spin field effect transistors (spin FETs)? Room temperature magnetic semiconductors are considered to be one promising candidate, and are listed as one of 125 scientific puzzles by Science in 2005. However, the growth of room-temperature magnetic semiconductors has not been successful, and it has been a great challenge to construct a spin FET that works at room temperature under atmospheric conditions.
The researchers from the National Center for Nanoscience and Technology (NCNST) of the Chinese Academy of Sciences (CAS), have successfully constructed a four-terminal spin FET based on the local giant magnetic moment effect. This work was published in Nano Today.
In this work, researchers designed a partially open structure based on an individual semiconducting single-walled carbon nanotube (SWNT). Two segments along its length were opened by a metal electrode perpendicularly connected to the SWNT. When the conventional charge current flows through the left electrode, an accumulation of spin-up will diffuse along the SWNT and cause spin current due to the magnetic moment. This phenomenon results in a measurable spin induced voltage Vspin and the detection of spin current is achieved. Additionally, the spin-related signal (Rspin) can be as high as hundreds of ohms, meanwhile the spin FET works under atmospheric conditions at room temperature. Importantly, the spin signal can be controlled by the gate voltage, and also effectively adjusted by the X, Y, and Z direction magnetic fields, proving that it is originated from spin and spin current. Because the unique hysteresis loop is related to the magnetic moment, the spin FET is non-volatile, low energy consumption, which can be used for information storage and calculation.
The work was financially supported by Major Nanoprojects of Ministry of Science and Technology of China, National Natural Science Foundation of China, The GBA National Institute for Nanotechnology Innovation, Baotou Rare Earth Research and Development Centre, CAS, Strategic Priority Research Program of CAS.