31 Result(s)
within
H. Katayama-Yoshida
-
Article
Materials Design for the Low-Resistivity in p-Type ZnO and Transparent Ferromagnet With Transition Metal Atom Doped ZnO: Prediction vs. Experiment
We propose a new valence control method of codo** with do** Ga (or In, Al) donor and N acceptor at the same time for the fabrication of a low-resistivity p-type ZnO based upon theab initio calculation. We com...
-
Article
Ab initio materials design for transparent-conducting-oxide-based new-functional materials
Based upon ab initio electronic structure calculations for delafossite CuAlO2 and ZnO, we report on the design of new-functional materials for transparent conducting oxides (TCO), such as (i) low-resistive p-type...
-
Article
Is High TC Possible in (Ga,Mn)N?: Monte Carlo Simulation vs. Mean Field Approximation
The magnetic properties of diluted magnetic semiconductors (DMSs) are calculated from first-principles by map** the ab initio results on a classical Heisenberg model. By using the Korringa–Kohn–Rostoker coheren...
-
Article
Carrier Co-do** Method with Size Compensation to Enhance TC of Mn-doped Nitrides
Based on ab initio electronic structure calculations of Mn-doped III–V nitrides (AlN, GaN, InN), a co-do** method with size compensation to enhance the Curie temperature (TC) of Nitride-based DMS is proposed. T...
-
Article
First-Principles Study of Ferromagnetism in Mn-Doped GaN
We investigate the magnetic properties of Mn-doped GaN through first-principles pseudopotential calculations within the spin-density-functional approximation. We examine the nature of magnetic interactions bet...
-
Chapter and Conference Paper
Exchange Interactions and Curie Temperatures in Dilute Magnetic Semiconductors
We discuss the origin of ferromagnetism in dilute magnetic semiconductors based on ab initio calculations for Mn-doped GaN, GaP, GaAs and GaSb. We use the Korringa-Kohn- Rostoker method in connection with the ...
-
Article
Exchange Interactions and Curie Temperatures in Dilute Magnetic Semiconductors
We discuss the origin of ferromagnetism in dilute magnetic semiconductors based on ab initio calculations for Mn-doped GaN, GaP, GaAs and GaSb. We use the Korringa–Kohn–Rostoker method in connection with the c...
-
Article
Curie Temperatures of III–V Diluted Magnetic Semiconductors Calculated from First-Principles in Mean Field Approximation
Electronic structure and ferromagnetism in III–V compound-based diluted magnetic semiconductors (DMS) are investigated based on first-principles calculations by using the Korringa-Kohn-Rostoker method combined...
-
Article
Theoretical Aspects of Do** of Photovoltaic Materials
The low-resistive p- and n-type transparent conductors are necessary for the efficient photovoltaic (PV) solar cells. We review a new valence control method of co-do** with do** Ga- (or In-, or Alsubstitution...
-
Article
Hyperfine Interactions and Magnetism of 3d Transition-Metal-Impurities in II–VI and III–V Compound-Based Diluted Magnetic Semiconductors
The electronic structure of II–VI and III–V compound-based diluted magnetic semiconductors is calculated based on the local density approximation (LDA) using the Korringa–Kohn–Rostoker method combined with the...
-
Article
Role ofn-Type Codopants on Enhancingp-Type Dopants Incorporation inp-Type Codoped Znse
We propose materials design for the fabrication of low-resistivityp-type ZnSe crystals using a new do** method which involves simultaneous codo** of bothn- andp-type dopants, based on theab initio electronic ...
-
Chapter and Conference Paper
ab initio Electronic Structure Calculation of Atomic Displacement of Defects in Semiconductors Induced by Electronic Excitation
We discuss the mechanism of atomic displacements of defects induced by electronic excitation in semiconductors based upon ab initio quantum-molecular-dynamics simulations and a pseudo Jahn-Teller interaction. Ele...
-
Article
Electronic Structures of P-Type Doped CuInS2
We have studied the electronic structures of CuIn(S0.875X0.125)2 (X=B, C, N, Si or P) based on the ab-initio electronic band structure calculations using the augmented spherical wave (ASW) method. We have clarifi...
-
Article
Vacancy-Interstitial Pair-Formation Mechanism of X-Ray-Irradiation-Induced Crystallization in Amorphous Silicon Studied by ab initio Molecular Dynamics Simulation
We have studied the microscopic mechanism of the X-ray-irradiation-enhanced crystallization in amorphous silicon (a-Si) based upon an ab initio molecular-dynamics simulation. We find that the bistable dangling-bo...
-
Article
Electronic Structure and Dynamics of Defect in a-Si:H By AB-Initio Molecular Dynamics
Electronic structure and dynamics of defects in hydrogenated amorphous silicon (a-Si:H) are investigated based upon ab-initio molecular-dynamics simulations. It is shown that (i) the hydrogen-passivated dangling ...
-
Chapter and Conference Paper
Angle-Resolved Photoemission and Inverse Photoemission Study of Bi2Sr2Ca1-xYxCu2O8 (x=0.0 and 0.6)
Angle-resolved photoemission (ARPES) and inverse photoemission (ARIPES) measurements were performed on Bi2Sr2Ca1-xYxCu2O8 (x=0.0 and 0.6). The ARIPES result suggests that there are two bands crossing the Fermi le...
-
Chapter and Conference Paper
De Haas-van Alphen Effect in YBa2Cu3O7
The de Haas-van Alphen effect has been measured in magnetically oriented YBa2Cu3O7 powder in steady high magnetic fields up to 27T with the modulation technique. A broad band centered at 540T, which corresponds t...
-
Chapter and Conference Paper
Polarized Cu LIII Absorption Study of Bi2Sr2Ca1-xYxCu2O8 (x=0.0 and 0.6)
Copper LIII absorption spectra were measured for Bi2Sr2Ca1-xYxCu2O8 (x=0.0 and 0.6) single crystals at various incident angles with linearly polarized synchrotron radiation. The absorption spectrum of either supe...
-
Chapter and Conference Paper
Unoccupied Electronic Structure of Bi2Sr2Ca1−xYxCu2O8 Studied by Inverse Photoemission
Inverse photoemission spectroscopy has been performed for Bi2Sr2Ca1−xYxCu2O8 single crystal (x=0.0) and ceramics samples (x=0.0, 0.3 and 0.5) to investigate the unoccupied electronic structure. Angle-resolved mea...
-
Chapter and Conference Paper
de Haas-van Alphen Measurement in YBa2Cu3O7
Measurements of de Haas van Alphen effect have been carried out using modulation technique in steady high magnetic fields up to 27T at the temperatures range between 1.8 and 4.2K. A broad band centering at 540...
