Low dimensional materials are suitable candidates applying in next-generation high-performance electronic,optoelectronic,and energy storage devices because of their uniquely physical and chemical properties.In particu...Low dimensional materials are suitable candidates applying in next-generation high-performance electronic,optoelectronic,and energy storage devices because of their uniquely physical and chemical properties.In particular,one-dimensional(1D)atomic wires(AWs)exfoliating from 1D van der Waals(vdW)bulks are more promising in next generation nanometer(nm)even sub-nm device applications owing to their width of few-atoms scale and free dandling bonds states.Although several 1D AWs have been experimentally prepared,few 1D AW candidates could be practically applied in devices owing to lack of enough suitable 1D AWs.Herein,367 kinds of 1D AWs have been screened and the corresponding computational database including structures,electronic structures,magnetic states,and stabilities of these 1D AWs has been organized and established.Among these systems,unary and binary 1D AWs with relatively small exfoliation energy are thermodynamically stable and theoretically feasible to be exfoliated.More significantly,rich quantum states emerge,such as 1D semiconductors,1D metals,1D semimetals,and 1D magnetism.This database will offer an ideal platform to further explore exotic quantum states and exploit practical device applications using 1D materials.The database are openly available at http://www.dx.doi.org/10.11922/sciencedb.j00113.00004.展开更多
We study the electronic and magnetic properties of an oxygen-deficient perovskite Ca2Mn2O5 based on the first principle calculations. The calculations show that the ground state of Ca2Mn2O5 is a D-type anti-ferromagne...We study the electronic and magnetic properties of an oxygen-deficient perovskite Ca2Mn2O5 based on the first principle calculations. The calculations show that the ground state of Ca2Mn2O5 is a D-type anti-ferromagnetic structure with the anti-ferromagnetic spin coupling along the c-direction. The corresponding electronic structure of the D-type state is investigated, and the results display that Ca2Mn2O5 is an insulator with an indirect energy gap of -2.08eV. By the partiM density-of-state analysis, the valence band maximum is mainly contributed to by the 0-213 orbitMs and the conduction band minimum is contributed to by the 0-213 and Mn-3d orbitals. Due to the Coulomb repulsion interaction between electrons, the density of state of Mn-3d is pulled to -6--4.5eV.展开更多
Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（C...Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（Cu2O）1-x deposition. Room-temperature ferromagnetism（FM） is found in all of the samples. The saturated magnetization increases at first and then decreases with the decrease of x. The photoluminescence spectra show that the magnetization is closely correlated with the Cu vacancies in the Cux（Cu2O）1-x granular films. Fundamentally, the FM could be understood by the Stoner model based on the charge transfer mechanism. These results may provide solid evidence and physical insights on the origin of FM in the Cu2O-based oxides diluted magnetic semiconductors, especially for systems without intentional magnetic atom doping.展开更多
A large amount of ultra-low-power consumption electronic devices are urgently needed in the new era of the internet of things,which demand relatively low frequency response.Here,atomic layer deposition has been utiliz...A large amount of ultra-low-power consumption electronic devices are urgently needed in the new era of the internet of things,which demand relatively low frequency response.Here,atomic layer deposition has been utilized to fabricate the ion polarization dielectric of the Li PON-Al_(2)O_(3) hybrid structure.The Li PON thin film is periodically stacked in the Al_(2)O_(3) matrix.This hybrid structure presents a frequency-dependent dielectric constant,of which k is significantly higher than the aluminum oxide matrix from 1 k Hz to 200 k Hz in frequency.The increased dielectric constant is attributed to the lithium ions shifting locally upon the applied electrical field,which shows an additional polarization to the Al_(2)O_(3) matrix.This work provides a new strategy with promising potential to engineers for the dielectric constant of the gate oxide and sheds light on the application of electrolyte/dielectric hybrid structure in a variety of devices from capacitors to transistors.展开更多
基金the National Key Research and Development Program of China(Grant No.2017YFE0129000)the National Natural Science Foundation of China(Grant Nos.51871121,11874223,and 11404172).
文摘Low dimensional materials are suitable candidates applying in next-generation high-performance electronic,optoelectronic,and energy storage devices because of their uniquely physical and chemical properties.In particular,one-dimensional(1D)atomic wires(AWs)exfoliating from 1D van der Waals(vdW)bulks are more promising in next generation nanometer(nm)even sub-nm device applications owing to their width of few-atoms scale and free dandling bonds states.Although several 1D AWs have been experimentally prepared,few 1D AW candidates could be practically applied in devices owing to lack of enough suitable 1D AWs.Herein,367 kinds of 1D AWs have been screened and the corresponding computational database including structures,electronic structures,magnetic states,and stabilities of these 1D AWs has been organized and established.Among these systems,unary and binary 1D AWs with relatively small exfoliation energy are thermodynamically stable and theoretically feasible to be exfoliated.More significantly,rich quantum states emerge,such as 1D semiconductors,1D metals,1D semimetals,and 1D magnetism.This database will offer an ideal platform to further explore exotic quantum states and exploit practical device applications using 1D materials.The database are openly available at http://www.dx.doi.org/10.11922/sciencedb.j00113.00004.
基金Supported by the National Basic Research Program of China under Grant No 2014CB931703the National Natural Science Foundation of China under Grant Nos 11404172,51101088,and 51171082the Fundamental Research Funds for the Central Universities
文摘We study the electronic and magnetic properties of an oxygen-deficient perovskite Ca2Mn2O5 based on the first principle calculations. The calculations show that the ground state of Ca2Mn2O5 is a D-type anti-ferromagnetic structure with the anti-ferromagnetic spin coupling along the c-direction. The corresponding electronic structure of the D-type state is investigated, and the results display that Ca2Mn2O5 is an insulator with an indirect energy gap of -2.08eV. By the partiM density-of-state analysis, the valence band maximum is mainly contributed to by the 0-213 orbitMs and the conduction band minimum is contributed to by the 0-213 and Mn-3d orbitals. Due to the Coulomb repulsion interaction between electrons, the density of state of Mn-3d is pulled to -6--4.5eV.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11104148,51101088,and 51171082)the Tianjin Natural Science Foundation,China(Grant Nos.14JCZDJC37700 and 13JCQNJC02800)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20110031110034)the Fundamental Research Funds for the Central Universities,China
文摘Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（Cu2O）1-x deposition. Room-temperature ferromagnetism（FM） is found in all of the samples. The saturated magnetization increases at first and then decreases with the decrease of x. The photoluminescence spectra show that the magnetization is closely correlated with the Cu vacancies in the Cux（Cu2O）1-x granular films. Fundamentally, the FM could be understood by the Stoner model based on the charge transfer mechanism. These results may provide solid evidence and physical insights on the origin of FM in the Cu2O-based oxides diluted magnetic semiconductors, especially for systems without intentional magnetic atom doping.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2018YFB2200500and 2018YFB2200504)the National Natural Science Foundation of China(Grant Nos.22090010,22090011,and61504070)。
文摘A large amount of ultra-low-power consumption electronic devices are urgently needed in the new era of the internet of things,which demand relatively low frequency response.Here,atomic layer deposition has been utilized to fabricate the ion polarization dielectric of the Li PON-Al_(2)O_(3) hybrid structure.The Li PON thin film is periodically stacked in the Al_(2)O_(3) matrix.This hybrid structure presents a frequency-dependent dielectric constant,of which k is significantly higher than the aluminum oxide matrix from 1 k Hz to 200 k Hz in frequency.The increased dielectric constant is attributed to the lithium ions shifting locally upon the applied electrical field,which shows an additional polarization to the Al_(2)O_(3) matrix.This work provides a new strategy with promising potential to engineers for the dielectric constant of the gate oxide and sheds light on the application of electrolyte/dielectric hybrid structure in a variety of devices from capacitors to transistors.
