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Search Results: 1 - 10 of 88122 matches for " FENG Hong-Jian "
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Coupling of magnetization and structural distortions in multiferroic BiFeO3 : an ab initio density functional theory study
Hong-Jian Feng
Physics , 2007, DOI: 10.1088/0256-307X/25/2/086
Abstract: This paper has been withdrawn by the author due to a crucial citing error in equation 4.
Electronic structures and lattice dynamics of BaTiO3 and BiFeO3 : a comparative first-principles study
Hong-Jian Feng
Physics , 2007,
Abstract: First-principles calculations were performed to investigate the ferroelectric properties of barium titanate and bismuth ferrite, as well as phonon dispersion of BaTiO3, using density functional theory and density functional perturbation theory. Results show that the strong hybridization of Ti-O and Bi-O lead to the corresponding mechanisms for stabilizing the distorted structure. The spontaneous polarization of 59.4 \mu C/cm2 and 27.6 \mu C/cm2 were calculated for BiFeO3 and BaTiO3 respectively, using berry phase method within the modern theory of polarization. The stereochemical activity of Bi-6s long-pair, which was the driven mechanism for ferroelectricity in BiFeO3, was able to produce greater polarization than the Ti off-centring displacement in BaTiO3. New multiferroic perovskite type materials combined with these two ferroelectric instabilities were predicted to have a better ferromagnetic ordering in comparison with BiFeO3.
Spin transfer in ultrathin BiFeO3 film under external electric field
Hong-Jian Feng
Physics , 2012, DOI: 10.1209/0295-5075/101/67007
Abstract: First-principals calculations show that up-spin and down-spin carriers are accumulating adjacent to opposite surfaces of BiFeO3(BFO) film with applying external bias. The spin carriers are equal in magnitude and opposite in direction, and down-spin carriers move to the direction opposing the external electric field while up-spin ones along the field direction. This novel spin transfer properties make BFO film an intriguing candidate for application in spin capacitor and BFO-based multiferroic field-effect device.
Magnetism and electronic properties of BiFeO3 under lower pressure
Hong-Jian Feng
Physics , 2012, DOI: 10.1016/j.jmmm.2010.07.034
Abstract: Ab initio calculations show an antiferromagnetic-ferromagnetic phase transition around 9-10 GPa and a magnetic anomaly at 12 GPa in BiFeO3. The magnetic phase transition also involves a structural and insulator-metal transition. The G-type AFM configuration under pressure leads to an increase of the y component and decrease of the z component of the magnetization, which is caused by the splitting of the dz2 orbital from doubly degenerate eg states. Our results agree with recent experimental results.
The role of Coulomb and exchange interaction on the Dzyaloshinskii-Moriya interaction(DMI) in BiFeO3
Hong-Jian Feng
Physics , 2012, DOI: 10.1016/j.jmmm.2009.12.025
Abstract: Ab initio calculations show that the Dzyaloshinskii-Moriya interaction(DMI)and net magnetization per unit cell in BiFeO3 are reduced when U is increasing from 0 to 2.9 eV, and independent of $J$. Interestingly, the DMI is even destroyed as $U$ exceeds a critical value of 2.9 eV. We propose a simple model to explain this phenomenon and present the nature of the rotation of the magnetization corresponding to altered antiferrodistortive distortions under DMI in BiFeO3.
The reversal of magnetization driven by the Dzyaloshinskii-Moriya interaction(DMI) in perovskite Bi2FeMnO6
Hong-Jian Feng
Physics , 2012, DOI: 10.1016/j.jmmm.2011.08.005
Abstract: Ab initio calculations show that the coupling between antiferrodistortive(AFD) distortions and magnetization in perovskite Bi2FeMnO6 is prohibited to make magnetization rotate as on-site Coulomb interaction($U$) is larger than 2.7 eV, where anomalies in antiferromagnetic(AFM) vectors and band gap varying with on-site Coulomb interaction can be observed. This coupling is attributed to the antisymmetric Dzyaloshinskii-Moriya interaction(DMI) driven by the eg-eg states AFM interaction and charge redistribution with respect to different AFD distortions.
Electric-field switching magnetization and spin transfer in ultrathin BiFeO3 film
Hong-Jian Feng
Physics , 2013,
Abstract: First-principles density-functional theory calculations show switching magnetization by 90 degree can be achieved in ultrathin BFO film by applying external electric-field. Up-spin carriers appear to the surface with positive field while down-spin ones to the negative field surface, arising from the redistribution of Fe-t2g orbital. The half-metallic behavior of Fe-3d states in the surface of R phase film makes it a promising candidate for AFM/FM bilayer heterostructure possessing electric-field tunable FM magnetization reversal and opens a new way towards designing spintronic multiferroics. The interface exchange-bias effect in this BFO/FM bilayer is mainly driven by the Fe-t2g orbital reconstruction, as well as spin transferring and rearrangement.
Photovoltaic effect in BiFeO3/TiO2 heterostructures tuned with epitaxial strain and an electric field
Hong-Jian Feng,Artem R. Oganov
Physics , 2013,
Abstract: The photovoltaic effect in the BiFeO3/TiO2 heterostructures can be tuned by epitaxial strain and an electric field in the visible-light region which is manifested by the enhancement of absorption activity in the heterojunction under tensile strain and an electric field based on the first-principles calculations. It is suggested that there are coupling between photon, spin carrier, charge, orbital, and lattice in the interface of the bilayer film which makes the heterojunction an intriguing candidate towards fabricating the multifunctional photoelectric devices based on spintronics. The microscopic mechanism involved in the heterostruces is related deeply with the spin transfer and charge rearrangement between the Fe 3d and O 2p orbitals in the vicinity of the interface.
Electronic structures and magnetoelectric properties of tetragonal BaFeO3: an ab initio density functional theory study

Feng Hong-Jian,Liu Fa-Min,

中国物理 B , 2008,
Ab initio prediction on ferrotoroidic and electronic properties of olivine Li4MnFeCoNiP4O16

Feng Hong-Jian,Liu Fa-Min,

中国物理 B , 2009,
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