Source: WeChat public account "Research Scientific Research"
Recently, the research team of Academician Yang Jinlong of the University of Science and Technology of China proposed a standard strategy for bipolar magnetic semiconductor (BMS) screening, and based on this strategy, 11 intrinsic BMS materials were screened, including a Li2V3TeO8 material with room temperature intrinsic ferromagneticity. The relevant results of
were titled "High-throughput Computational Screening for Bipolar Magnetic Semiconductors" and were published on Research.
Research background
Spinel electronics device uses electron spins to transmit, process and store information. Compared with traditional microelectronics devices, it has potential advantages such as fast computing speed and low energy consumption .
However, spin can generally be controlled by magnetic fields, which makes it difficult to achieve miniaturization and integration of devices. Using electric field to regulate can solve this contradiction.
Therefore, how to use electric fields to regulate the spin of electrons is one of the key scientific problems facing spin electronics.
To solve this problem, Yang Jinlong's team initially proposed a new type of spintronics material, namely bipolar magnetic semiconductor (Bipolar Magnetic Semiconductors, BMS) [Natl. Sci. Rev. 2016, 3, 365].
This kind of materials is unique in that their conduction band has opposite spin polarization directions to the edge of the valence band. Therefore, the position of the Fermi energy level can be adjusted by applying the gate voltage , so that it can provide electrons with different spin orientations, breaking through the traditional model of using magnetic fields to regulate spins, and providing a new idea for the development of the new spin electronics device for electric field regulation .
However, finding bipolar magnetic semiconductor materials with intrinsic ferromagneticity has always been a difficult problem.
Research progress
In this work, Yang Jinlong's team proposed a standard high-throughput calculation filtering strategy for BMS material search, which includes primary filtering and secondary filtering (Figure 1).
primary filter by using conventional fast density functional methods such as PBE+U to investigate initialization, magnetic properties, stability, bandgap and doping properties in turn, while secondary filter performs more fine screening of magnetic sequence, magnetic exchange energy and band calculations using more precise hybrid functional methods and quasi-particle methods.
Based on this dual screening strategy, the researchers used the Materials Project crystal database as an example to screen 11 intrinsic BMS materials (including 1 experimentally prepared material and 10 theoretically proposed materials) from ~40,000 structures.
One of the BMS material Li2V3TeO8 (mp-771246) has room temperature intrinsic ferromagnetic , and its Curie temperature is as high as 478 K.
Figure 1 (a) Primary filter (b) Statistical analysis of BMS screening (c) Secondary filter
It is worth noting that Li2V3TeO8 material also has the following two advantages.
1) Compared with the experimental phases LiVTeO5 and LiV3(TeO6)2, the Li2V3TeO8 phase has a lower enthalpy of , which makes it have certain synthesis possibilities in experiments;
2) When cutting Li2V3TeO8 in the bulk phase into (001-side) nanofilms, it can still maintain BMS characteristics well, which makes it have great potential in the application of nanospinelectronic devices.
Figure 2 Li2V3TeO8 (001 side) film DOS changes with the number of layers
Future prospects
This research work provides a feasible solution for discovering new intrinsic BMS materials from various crystal structure databases, which can effectively improve the search and design efficiency of BMS materials and pave the way for the development of spintronics.
However, there are calculation errors in some data in the Materials Project database, resulting in some potential BMS materials not being correctly screened out.
Therefore, high-quality data set is a problem that needs to be solved urgently in the future.
At the same time, in the future, it is also a feasible method to establish structure-performance relationships based on existing BMS materials, and using machine learning methods to predict new BMS.
Author profile
- Yang Jinlong
Hang Jinlong, an academician of the Chinese Academy of Sciences and a professor at the University of Science and Technology of China, has long been committed to applied quantum chemistry research, and has achieved original and systematic results in the design and simulation of new functional materials, the characterization and regulation of surface single molecule quantum behavior, and has had an important impact at home and abroad.
has published more than 540 papers included in SCI (280 first and corresponding authors), including 3 Science, 5 NatureJ. Am. Chem. Soc. , 13 articles Angew. Chem. Int. Ed. and 14 articles Phys. Rev. Lett. .
was invited to give invitation reports and conference reports more than 120 times at domestic and international academic conferences.
presided over major national scientific research projects (two times), national key R&D plan projects and innovative research groups of the Foundation Committee.
- Li Xingxing
Associate Professor Li Xingxing has long been committed to research on material design, characterization and device simulation based on first principles.
is guided by the current two important issues of information and energy, focusing on three aspects: spin information material design, single-molecular electronic information device simulation, and energy conversion catalytic mechanism analysis, and has carried out in-depth systematic theoretical research, and has achieved many important results, providing theoretical ideas and routes for guiding and promoting related experimental research. For example, a type of spin information material, namely bipolar magnetic semiconductor (BMS), is proposed and developed, which provides solutions to the problem of spin electrical regulation; in situ electrical characterization of hydrogen bond kinetics is realized in single-molecular devices, laying the foundation for information processing using hydrogen bonds; an infrared photodecomposition water hydrogen production mechanism is proposed, paving the way for the full spectrum of solar energy.
So far in Nature Communications, Science Advances, JACS, PRL, , Angew, Nano Famous SCI journals such as Letters and other famous SCI journals have published 34 papers in the first, one and a total of 34 corresponding authors, with a total of more than 2,000 citations.
was selected as a member of the Youth Innovation Promotion Association of the Chinese Academy of Sciences.
