Browsing by Author "Chiu, Ya-Ping"

Now showing 1 - 14 of 14

A Metal-Insulator Transition of the Buried MnO2 Monolayer in Complex Oxide Heterostructure
(2016-11-02)
Liu, Heng-Jui
;
Lin, Jheng-Cyuan
;
Fang, Yue-Wen
;
Wang, Jing-Ching
;
Huang, Bo-Chao
A novel artificially created MnO2 monolayer system is demonstrated in atomically controlled epitaxial perovskite heterostructures. With careful design of different electrostatic boundary conditions, a magnetic transition as well as a metal-insulator transition of the MnO2 monolayer is unveiled, providing a fundamental understanding of dimensionality-confined strongly correlated electron systems and a direction to design new electronic devices.
An electrically switchable surface free energy on a liquid crystal and polymer composite film
(2012-12-03)
Lin, Yi-Hsin
;
Chu, Ting-Yu
;
Tsou, Yu-Shih
;
Chang, Kai-Han
;
Chiu, Ya-Ping
An electrically switchable surface free energy on a liquid crystal and polymer composite film (LCPCF) resulting from the orientations of liquid crystal molecules is investigated. By modification of Cassie's model and the measurement based on the Chibowski's film pressure model (E. Chibowski, Adv. Colloid Interface Sci. 103, 149 (2003)), the surface free energy of LCPCF is electrically switchable from 36 x 10(-3)J/m(2) to 51 x 10(-3)J/m(2) while the average tilt angle of LC molecules changes from 0 degrees to 32 degrees with the applied pulsed voltage. The switchable surface free energy of LCPCF can help us to design biosensors and photonics devices, such as electro-optical switches, blood sensors, and sperm testers. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4769093]
Anisotropic superconductivity induced by periodic multiferroic domain patterns
(2019-12-06)
Huang, Yen-Lin
;
Huang, Bo-Chao
;
Wang, Yan-Ting
;
Xue, Fei
;
Lin, Jheng-Cyuan
The competition between order parameters, such as ferroelectricity, ferromagnetism, and superconductivity, is one of the most fascinating topics in condensed matter physics. Here, we report intriguing anisotropic superconductivity in YBa2Cu3O7-x films induced by a multiferroic, BiFeO3, with periodic domain patterns. The anisotropic superconductivity was investigated by transport measurements and supported by phase-field simulations, and then the detailed local electronic structures were revealed by cross-sectional scanning tunneling microscopy. We found that the oxygen redistribution in YBa2Cu3O7-x modulated by the ferroelectric polarization in BiFeO3 was the key mechanism driving this anisotropic superconductivity. The presented heteroarchitecture of a high-temperature superconductor and a domain-engineered multiferroic provides a new approach to tune superconductivity and offers potential advantages for the design of future multifunctional devices.
Atomic-Scale Evolution of Local Electronic Structure Across Multiferroic Domain Walls
(2011-04-05)
Chiu, Ya-Ping
;
Chen, Yu-Ting
;
Huang, Bo-Chao
;
Shih, Min-Chuan
;
Yang, Jan-Chi
Direct evidence of the electronic configurations across domain walls in BiFeO(3) is quantitatively characterized by cross-sectional scanning tunneling microscopy. Atomic-scale band evolution and the asymmetrically built-in potential barrier at domain boundaries are demonstrated. The 109 degrees domain walls register a remarkable decrease in the bandgap, suggesting a new route to control the local conducting channels within 2 nm.
Atomically Resolved Electronic States and Correlated Magnetic Order at Termination Engineered Complex Oxide Heterointerfaces
(2018-02-01)
Huang, Bo-Chao
;
Yu, Pu
;
Chu, Y. H.
;
Chang, Chia-Seng
;
Ramesh, Ramamoorthy
We map electronic states, band gaps, and interface-bound charges at termination-engineered BiFeO3/La0.7Sr0.3MnO3 interfaces using atomically resolved cross-sectional scanning tunneling microscopy. We identify a delicate interplay of different correlated physical effects and relate these to the ferroelectric and magnetic interface properties tuned by engineering the atomic layer stacking sequence at the interfaces. This study highlights the importance of a direct atomically resolved access to electronic interface states for understanding the intriguing interface properties in complex oxides.
Characteristics of Electrically Switchable Wettability Surfaces of Liquid Crystal and Polymer Composite Films
(2010)
Chiu, Ya-Ping
;
Shen, Cheng-Yu
;
Lin, Yi-Hsin
;
光電工程學系
;
Department of Photonics
Experimentally, the electrically controllable surface wettability of liquid crystal and polymer composite film has been demonstrated. In the work, scanning probe microscopy has been used to investigate the surface characterization of liquid crystal molecular units at a polymer surface under external voltages applied. The surface morphologies as well as the sensitivity of measurement to surface adhesive force on the nanoscale are determined quantitatively for such unique nano-sized liquid crystals/polymer composite films. The surface wettability of the films deduced from the local adhesion properties demonstrated the electrical control of surface wettability properties, suggesting that the interfacial liquid-crystal molecular alignment of the films with external voltage applied should have significant influence on the modification of the surface characterization of liquid crystals. (C) 2010 The Japan Society of Applied Physics
Control of the Metal-Insulator Transition at Complex Oxide Heterointerfaces through Visible Light
(2016-01-27)
Lin, Jheng-Cyuan
;
Vu Thanh Tra
;
Tsai, Dung-Sheng
;
Lin, Tai-Te
;
Huang, Po-Cheng
The coupling of the localized surface plasmon resonance of Au nanoparticles is utilized to deliver a visible-light stimulus to control conduction at the LaAlO3/SrTiO3 interface. A giant photoresponse and the controllable metal-insulator transition are characterized at this heterointerface. This study paves a new route to optical control of the functionality at the heterointerfaces.
Current Developments for Taiwanese Women in Physics
(2015)
Hsu, Shih-Ying
;
Ho, Mon-Shu
;
Lin, Jauyn Grace
;
Hu, Shu-Fen
;
Chiu, Ya-Ping
Statistics for 2002 to 2012 show that the percentage of women among graduates in physics and astronomy has not changed much in the Republic of China in Taiwan. Women comprise about 15% of graduates with bachelor\'s degrees in physics and astronomy, 17% of those with master\'s degrees, and 12% of doctorates. The number of female faculty members has increased slightly during this time frame but overall has stayed at approximately 11%.
Electrically surface-driven switchable wettability of liquid crystal/polymer composite film
(2010-03-29)
Chiu, Ya-Ping
;
Shen, Cheng-Yu
;
Wang, Wen-Ching
;
Chu, Ting-Yu
;
Lin, Yi-Hsin
This study demonstrates the electrical control of the surface wettability of liquid crystal and polymer composite film. The application of external voltages significantly affects the surface wettability of the film. This study uses atomic force microscopy to quantitatively characterize the fundamental mechanism responsible for the structurally driven changes in surface properties at various applied voltages. The surface wettability transitions of the film are electrically driven, as shown by reorganized liquid crystal molecules. Measurements of the voltage-dependent surface wettability of the composite film suggest approaches to supporting control applications of future electro-optical nanotechnology devices.
Ferroelectric Control of the Conduction at the LaAlO3/SrTiO3 Heterointerface
(2013-06-25)
Vu Thanh Tra
;
Chen, Jhih-Wei
;
Huang, Po-Cheng
;
Huang, Bo-Chao
;
Cao, Ye
Giant Photoresponse in Quantized SrRuO3 Monolayer at Oxide Interfaces
(2018-03-01)
Liu, Heng-Jui
;
Wang, Jing-Ching
;
Cho, Deok-Yong
;
Ho, Kang-Ting
;
Lin, Jheng-Cyuan
The photoelectric effect in semiconductors is the main mechanism for most modern optoelectronic devices, in which the adequate bandgap plays the key role for acquiring high photoresponse. Among numerous material categories applied in this field, the complex oxides exhibit great possibilities because they present a wide distribution of band gaps for absorbing light with any wavelength. Their physical properties and lattice structures are always strongly coupled and sensitive to light illumination. Moreover, the confinement of dimensionality of the complex oxides in the heterostructures can provide more diversities in designing and modulating the band structures. On the basis of this perspective, we have chosen itinerary ferromagnetic SrRuO3 as the model material, and fabricated it in one-unit-cell thickness in order to open a small band gap for effective utilization of visible light. By inserting this SrRuO3 monolayer at the interface of the well-developed two-dimensional electron gas system (LaAlO3/SrTiO3), the resistance of the monolayer can be further revealed. In addition, a giant enhancement (>300%) of photoresponse under illumination of visible light with power density of 500 mW/cm(2) is also observed. Such can be ascribed to the further modulation of band structure of the SrRuO3 monolayer under the illumination, confirmed by cross-section scanning tunneling microscopy (XSTM). Therefore, this study demonstrates a simple route to design and explore the potential low dimensional oxide materials for future optoelectronic devices.
Local Conduction at the BiFeO3-CoFe2O4 Tubular Oxide Interface
(1970-01-01)
Hsieh, Ying-Hui
;
Liou, Jia-Ming
;
Huang, Bo-Chao
;
Liang, Chen-Wei
;
He, Qing
"In strongly correlated oxides, heterointerfaces, manipulating the interaction, frustration, and discontinuity of lattice, charge, orbital, and spin degrees of freedom, generate new possibilities for next generation devices. In this study, existing oxide heterostructures are examined and local conduction at the BiFeO3-CoFe2O4 vertical interface is found. In such heteronanostructures the interface cannot only be the medium for the coupling between phases, but also a new state of the matter. This study demonstrates a novel concept on for oxide interface design and opens an alternative pathway for the exploration of diverse functionalities in complex oxide interfaces."
Mapping Band Alignment across Complex Oxide Heterointerfaces
(2012-12-12)
Huang, Bo-Chao
;
Chiu, Ya-Ping
;
Huang, Po-Cheng
;
Wang, Wen-Ching
;
Vu Thanh Tra
In this study, direct observation of the evolution of electronic structures across complex oxide interfaces has been revealed in the LaAlO3/SrTiO3 model system using cross-sectional scanning tunneling microscopy and spectroscopy. The conduction and valence band structures across the LaAlO3/SrTiO3 interface are spatially resolved at the atomic level by measuring the local density of states. This study directly maps out the electronic reconstructions and a built-in electric field in the polar LaAlO3 layer. Results also clearly reveal the band bending and the notched band structure in the SrTiO3 adjacent to the interface. DOI: 10.1103/PhysRevLett.109.246807
Preface: 7th Vacuum and Surface Sciences Conference of Asia and Australia (VASSCAA-7)
(2015-11-01)
Chu, Jinn P.
;
Hsiung, Gao-Yu
;
Huang, Weixin
;
Luo, Meng-Fan
;
Chiu, Ya-Ping