Recently, many high-throughput calculation materials databases have been constructed and found wide applications. However, a database is only useful if its content is reliable and sufficiently accurate. It is thus of ...Recently, many high-throughput calculation materials databases have been constructed and found wide applications. However, a database is only useful if its content is reliable and sufficiently accurate. It is thus of paramount importance to gauge the reliabilities and accuracies of these databases. Although many properties have been predicted accurately in these databases,electronic band gap is well known to be underestimated by traditional density functional theory(DFT) calculations under local density approximation(LDA), which becomes a challenging problem for materials database building. Here, we introduce MaterialGo(http://www.pkusam.com/data-base.html), a new database calculating the band structures of crystals using both Perdew-Burke-Ernzerhof(PBE) exchange-correlation functional and Heyd-Scuseria-Ernzerhof(HSE) hybrid functional.Comparing different PBE databases, it is found that their band gaps are consistent when no U parameter is used for transition metal d-state or heavy element f-state to correct their self-interaction error, but rather different when PBE+U are used, mostly because of the different values of U used in different database. HSE calculations under standard parameters will give larger band gaps that are closer to experiment. Based on the high-throughput HSE calculations over 10000 crystal structures, we might have a better understanding of the relationship between crystal structures and electronic structures, which will help us to further explore material genome science and engineering.展开更多
The atomic size of each element, described by the ionic radius, is one category of "material genes" and can facilitate our understanding of atomic arrangements in compounds. Most of the ionic radii currently...The atomic size of each element, described by the ionic radius, is one category of "material genes" and can facilitate our understanding of atomic arrangements in compounds. Most of the ionic radii currently used to measure the sizes of cations and anions in ionic crystals are derived from hard-sphere model based on the coordination numbers, or the soft-sphere model incorporating the effect of ionic polarization. Herein we take a first step towards a novel "effective atomic size"(EAS) model,which takes into consideration the impact of the types and number of neighboring atoms on the relationship between ionic radii and interatomic distances. Taking the binary compounds between Group IA/IIA and VIA/VIIA elements gathered from the latest databases as an example, we show that the proposed EAS model can yield excellent agreement between the predicted and the DFT-calculated interatomic distances, with deviation of less than 0.1 ?. A set of EAS radii for ionic crystals has been compiled and the role of coordination numbers, geometric symmetry and distortion of structural units has been examined. Thanks to its superior predictability, the EAS model can serve as a foundation to analyze the structure of newly-discovered compounds and to accelerate materials screening processes in the future works.展开更多
基金supported by the National Key R&D Program of China(Grant No.2016YFB0700600)the Shenzhen Science and Technology Research Grant(Grant No.ZDSYS201707281026184)+1 种基金the Guangdong Key-lab Project(Grant No.2017B0303010130)Wang is supported by the Director Office of Science(SC)、Basic Energy Science(BES)、Materials Science and Engineering Division (MSED) of the US Department of Energy(DOE)under Contract No.DE-AC02-05CH11231 through the Materials Theory program(KC2301)
文摘Recently, many high-throughput calculation materials databases have been constructed and found wide applications. However, a database is only useful if its content is reliable and sufficiently accurate. It is thus of paramount importance to gauge the reliabilities and accuracies of these databases. Although many properties have been predicted accurately in these databases,electronic band gap is well known to be underestimated by traditional density functional theory(DFT) calculations under local density approximation(LDA), which becomes a challenging problem for materials database building. Here, we introduce MaterialGo(http://www.pkusam.com/data-base.html), a new database calculating the band structures of crystals using both Perdew-Burke-Ernzerhof(PBE) exchange-correlation functional and Heyd-Scuseria-Ernzerhof(HSE) hybrid functional.Comparing different PBE databases, it is found that their band gaps are consistent when no U parameter is used for transition metal d-state or heavy element f-state to correct their self-interaction error, but rather different when PBE+U are used, mostly because of the different values of U used in different database. HSE calculations under standard parameters will give larger band gaps that are closer to experiment. Based on the high-throughput HSE calculations over 10000 crystal structures, we might have a better understanding of the relationship between crystal structures and electronic structures, which will help us to further explore material genome science and engineering.
基金supported by the National Key R&D Program of China(Grant No.2016YFB0700600)the Shenzhen Science and Technology Research(Grant No.ZDSYS201707281026184)the Guangdong Key-Lab Project(Grant No.2017B0303010130)
文摘The atomic size of each element, described by the ionic radius, is one category of "material genes" and can facilitate our understanding of atomic arrangements in compounds. Most of the ionic radii currently used to measure the sizes of cations and anions in ionic crystals are derived from hard-sphere model based on the coordination numbers, or the soft-sphere model incorporating the effect of ionic polarization. Herein we take a first step towards a novel "effective atomic size"(EAS) model,which takes into consideration the impact of the types and number of neighboring atoms on the relationship between ionic radii and interatomic distances. Taking the binary compounds between Group IA/IIA and VIA/VIIA elements gathered from the latest databases as an example, we show that the proposed EAS model can yield excellent agreement between the predicted and the DFT-calculated interatomic distances, with deviation of less than 0.1 ?. A set of EAS radii for ionic crystals has been compiled and the role of coordination numbers, geometric symmetry and distortion of structural units has been examined. Thanks to its superior predictability, the EAS model can serve as a foundation to analyze the structure of newly-discovered compounds and to accelerate materials screening processes in the future works.
