High resolution angle resolved photoemission measurements and band structure calculations are carried out to study the electronic structure of BaMnSb_(2). All the observed bands are nearly linear that extend to a wide...High resolution angle resolved photoemission measurements and band structure calculations are carried out to study the electronic structure of BaMnSb_(2). All the observed bands are nearly linear that extend to a wide energy range. The measured Fermi surface mainly consists of one hole pocket around Γ and a strong spot at Y which are formed from the crossing points of the linear bands. The measured electronic structure of BaMnSb_(2) is unusual and deviates strongly from the band structure calculations. These results will stimulate further efforts to theoretically understand the electronic structure of BaMnSb_(2) and search for novel properties in this Dirac material.展开更多
We report polarization reversal periodically controlled by the electric field in multiferroic MnWO_(4) with a pulsed field up to 52 T.The electric polarization cannot be reversed by successive opposite electric fields...We report polarization reversal periodically controlled by the electric field in multiferroic MnWO_(4) with a pulsed field up to 52 T.The electric polarization cannot be reversed by successive opposite electric fields in low magnetic fields(<14 T)at 4.2 K,whereas polarization reversal is directly achieved by two opposite electric fields under high magnetic fields(<45 T).Interestingly,the polarization curve of rising and falling fields for H∥u(magnetic easy axis)is irreversible when the magnetic field is close to 52 T.In this case,the rising and falling polarization curves can be individually reversed by the electric field,and thus require five cycles to recover to the initial condition by the order of the applied electric fields(+E,-E,-E,+E,+E).In addition,we find that ferroelectric phaseⅣcan be tuned from parallel to antiparallel in relation to ferroelectric phase AF2 by applying a magnetic field approximated to the c axis.展开更多
The development of two-dimensional(2 D)high-performance electrode materials is the key to new advances in the fields of energy storage and conversion.As a novel family of 2 D layered materials,MXenes possess distinct ...The development of two-dimensional(2 D)high-performance electrode materials is the key to new advances in the fields of energy storage and conversion.As a novel family of 2 D layered materials,MXenes possess distinct structural,electronic and chemical properties that enable vast application potential in many fields,including batteries,supercapacitor and catalysis.However,MXene layers are easily formed by stacking together,which significantly reduces the specific surface area,hinders the transmission of ions,and restricts other functional materials on the surface,thereby reducing performance.In addition,due to the inherent defects of a single electrode material,electrodes or catalysts made of single-phase MXene may not meet specific practical application requirements.MXenes nanocomposites materials based on enhanced electrochemical performance through nanoengineering technology and surface modification for morphological control are highly sought after to solve these challenges.This review aims to present recent advances in these emerging MXene nanocomposites for energy storage and conversion applications such as batteries,supercapacitors and catalytic reactions.We also introduced some of the challenges and opportunities in this rapidly developing field.展开更多
基金supported by the National Key Research and Development Program of China (Grant Nos. 2016YFA0300600, 2018YFA0305602, 2016YFA0300300,2017YFA0302900)the National Natural Science Foundation of China (Grant Nos. 11974404, 11888101, 11922414, and 11404175)+8 种基金the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant Nos. XDB33000000 and XDB25000000)the Youth Innovation Promotion Association of CAS (Grant No. 2017013)the Natural Science Foundation of Henan Province,China (Grant Nos. 182300410274 and 202300410296)The theoretical calculations are supported by the National Natural Science Foundation of China (Grant Nos. 11674369, 11865019, and 11925408)the Beijing Natural Science Foundation,China (Grant No. Z180008)Beijing Municipal Science and Technology Commission,China (Grant No. Z191100007219013)the National Key Research and Development Program of China (Grant Nos. 2016YFA0300600 and 2018YFA0305700)the K. C. Wong Education Foundation (Grant No. GJTD-2018-01)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB33000000)。
文摘High resolution angle resolved photoemission measurements and band structure calculations are carried out to study the electronic structure of BaMnSb_(2). All the observed bands are nearly linear that extend to a wide energy range. The measured Fermi surface mainly consists of one hole pocket around Γ and a strong spot at Y which are formed from the crossing points of the linear bands. The measured electronic structure of BaMnSb_(2) is unusual and deviates strongly from the band structure calculations. These results will stimulate further efforts to theoretically understand the electronic structure of BaMnSb_(2) and search for novel properties in this Dirac material.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12074135,12104388,and 52272219)Nanyang Normal University,the Natural Science Foundation of Henan Province (Grant Nos.222300420255 and 232300421220)the Key Scientific and Technological Projiect of Technology Depeartment of Henan Province of China (Grant Nos.222102230105 and 212102210448)。
文摘We report polarization reversal periodically controlled by the electric field in multiferroic MnWO_(4) with a pulsed field up to 52 T.The electric polarization cannot be reversed by successive opposite electric fields in low magnetic fields(<14 T)at 4.2 K,whereas polarization reversal is directly achieved by two opposite electric fields under high magnetic fields(<45 T).Interestingly,the polarization curve of rising and falling fields for H∥u(magnetic easy axis)is irreversible when the magnetic field is close to 52 T.In this case,the rising and falling polarization curves can be individually reversed by the electric field,and thus require five cycles to recover to the initial condition by the order of the applied electric fields(+E,-E,-E,+E,+E).In addition,we find that ferroelectric phaseⅣcan be tuned from parallel to antiparallel in relation to ferroelectric phase AF2 by applying a magnetic field approximated to the c axis.
基金the National Natural Science Foundation of China(Nos.U1904215 and 21875207)the Natural Science Foundation of Jiangsu Province(No.BK20200044)Changjiang Scholars Program of the Ministry of Education(No.Q2018270)。
文摘The development of two-dimensional(2 D)high-performance electrode materials is the key to new advances in the fields of energy storage and conversion.As a novel family of 2 D layered materials,MXenes possess distinct structural,electronic and chemical properties that enable vast application potential in many fields,including batteries,supercapacitor and catalysis.However,MXene layers are easily formed by stacking together,which significantly reduces the specific surface area,hinders the transmission of ions,and restricts other functional materials on the surface,thereby reducing performance.In addition,due to the inherent defects of a single electrode material,electrodes or catalysts made of single-phase MXene may not meet specific practical application requirements.MXenes nanocomposites materials based on enhanced electrochemical performance through nanoengineering technology and surface modification for morphological control are highly sought after to solve these challenges.This review aims to present recent advances in these emerging MXene nanocomposites for energy storage and conversion applications such as batteries,supercapacitors and catalytic reactions.We also introduced some of the challenges and opportunities in this rapidly developing field.
