This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals,such as quantum dots and wires,which often contain ten...This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals,such as quantum dots and wires,which often contain tens of thousands of atoms.The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments.We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape.Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.展开更多
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
文摘This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals,such as quantum dots and wires,which often contain tens of thousands of atoms.The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments.We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape.Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.
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.
