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11 results on '"Wijesekara, Kanishka"'

4. Strain-Engineered Oxygen Vacancies in CaMnO₃ Thin Films

Author

Spaldin, Nicola A., Kobayashi, Keisuke, De Groot, Frank M. F., Kobata, Masaaki, Golalikhani, Maryam, Aschauer, Ulrich Johannes, Davidson, Bruce A., Delgado-Jaime, Mario U., Arenholz, Elke, Lei, Qingyu, Xi, Xiaoxing, Gray, Alexander X., Yang, Weibing, Wijesekara, Kanishka D., and Chandrasena, Ravini U.

Subjects
530 Physics, 540 Chemistry, 570 Life sciences, biology
Published
2017
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5. Strain-Engineered Oxygen Vacancies in CaMnO3 Thin Films

Author

Chandrasena, Ravini U., Yang, Weibing, Lei, Qingyu, Delgado Jaime, Mario, Wijesekara, Kanishka D., Golalikhani, Maryam, Davidson, Bruce A., Arenholz, Elke, Kobayashi, Keisuke, Kobata, Masaaki, De Groot, Frank M.F., Aschauer, Ulrich, Spaldin, Nicola A., Xi, Xiaoxing, Gray, Alexander X., Chandrasena, Ravini U., Yang, Weibing, Lei, Qingyu, Delgado Jaime, Mario, Wijesekara, Kanishka D., Golalikhani, Maryam, Davidson, Bruce A., Arenholz, Elke, Kobayashi, Keisuke, Kobata, Masaaki, De Groot, Frank M.F., Aschauer, Ulrich, Spaldin, Nicola A., Xi, Xiaoxing, and Gray, Alexander X.

Abstract

We demonstrate a novel pathway to control and stabilize oxygen vacancies in complex transition-metal oxide thin films. Using atomic layer-by-layer pulsed laser deposition (PLD) from two separate targets, we synthesize high-quality single-crystalline CaMnO3 films with systematically varying oxygen vacancy defect formation energies as controlled by coherent tensile strain. The systematic increase of the oxygen vacancy content in CaMnO3 as a function of applied in-plane strain is observed and confirmed experimentally using high-resolution soft X-ray absorption spectroscopy (XAS) in conjunction with bulk-sensitive hard X-ray photoemission spectroscopy (HAXPES). The relevant defect states in the densities of states are identified and the vacancy content in the films quantified using the combination of first-principles theory and core–hole multiplet calculations with holistic fitting. Our findings open up a promising avenue for designing and controlling new ionically active properties and functionalities of com...

Published
2017

6. Strain-Engineered Oxygen Vacancies in CaMnO3 Thin Films

Author

Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis, Chandrasena, Ravini U., Yang, Weibing, Lei, Qingyu, Delgado Jaime, Mario, Wijesekara, Kanishka D., Golalikhani, Maryam, Davidson, Bruce A., Arenholz, Elke, Kobayashi, Keisuke, Kobata, Masaaki, De Groot, Frank M.F., Aschauer, Ulrich, Spaldin, Nicola A., Xi, Xiaoxing, Gray, Alexander X., Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis, Chandrasena, Ravini U., Yang, Weibing, Lei, Qingyu, Delgado Jaime, Mario, Wijesekara, Kanishka D., Golalikhani, Maryam, Davidson, Bruce A., Arenholz, Elke, Kobayashi, Keisuke, Kobata, Masaaki, De Groot, Frank M.F., Aschauer, Ulrich, Spaldin, Nicola A., Xi, Xiaoxing, and Gray, Alexander X.

Published
2017

7. Strain-Engineered Oxygen Vacancies in CaMnO3 Thin Films

Author

Chandrasena, Ravini U., primary, Yang, Weibing, additional, Lei, Qingyu, additional, Delgado-Jaime, Mario U., additional, Wijesekara, Kanishka D., additional, Golalikhani, Maryam, additional, Davidson, Bruce A., additional, Arenholz, Elke, additional, Kobayashi, Keisuke, additional, Kobata, Masaaki, additional, de Groot, Frank M. F., additional, Aschauer, Ulrich, additional, Spaldin, Nicola A., additional, Xi, Xiaoxing, additional, and Gray, Alexander X., additional

Published
2017
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9. Strain-Engineered Oxygen Vacancies in CaMnO3 Thin Films.

Author

Chandrasena, Ravini U., Weibing Yang, Qingyu Lei, Delgado-Jaime, Mario U., Wijesekara, Kanishka D., Golalikhani, Maryam, Davidson, Bruce A., Arenholz, Elke, Keisuke Kobayashi, Masaaki Kobata, de Groot, Frank M. F., Aschauer, Ulrich, Spaldin, Nicola A., Xiaoxing Xi, and Gray, Alexander X.

Published
2017
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10. Spectroscopic Evidence of a Dimensionality-Induced Metal-to-Insulator Transition in the Ruddlesden-Popper La n +1 Ni n O 3 n +1 Series.

Author

Di Pietro P, Golalikhani M, Wijesekara K, Chaluvadi SK, Orgiani P, Xi X, Lupi S, and Perucchi A

Abstract

Perovskite-based heterostructures have recently gained remarkable interest, thanks to atomic-scale precision engineering. These systems are very susceptible to small variations of control parameters, such as two-dimensionality, strain, lattice polarizability, and doping. Focusing on the rare-earth nickelate diagram, LaNiO 3 (LNO) catches the eye, being the only nickelate that does not undergo a metal-to-insulator transition (MIT). Therefore, the ground state of LNO has been studied in several theoretical and experimental papers. Here, we show by means of infrared spectroscopy that an MIT can be driven by dimensionality control in ultrathin LNO films when the number of unit cells drops to 2. Such a dimensionality tuning can eventually be tailored when a physically implemented monolayer in the ultrathin films is replaced by a digital single layer embedded in the Ruddlesden-Popper La n +1 Ni n O 3 n +1 series. We provide spectroscopic evidence that the dimensionality-induced MIT in Ruddlesden-Popper nickelates strongly resembles that of ultrathin LNO films. Our results can pave the way to the employment of Ruddlesden-Popper La n +1 Ni n O 3 n +1 to tune the electronic properties of LNO through dimensional transition without the need of physically changing the number of unit cells in thin films.

Published
2021
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11. Strain-Engineered Oxygen Vacancies in CaMnO 3 Thin Films.

Author

Chandrasena RU, Yang W, Lei Q, Delgado-Jaime MU, Wijesekara KD, Golalikhani M, Davidson BA, Arenholz E, Kobayashi K, Kobata M, de Groot FM, Aschauer U, Spaldin NA, Xi X, and Gray AX

Abstract

We demonstrate a novel pathway to control and stabilize oxygen vacancies in complex transition-metal oxide thin films. Using atomic layer-by-layer pulsed laser deposition (PLD) from two separate targets, we synthesize high-quality single-crystalline CaMnO 3 films with systematically varying oxygen vacancy defect formation energies as controlled by coherent tensile strain. The systematic increase of the oxygen vacancy content in CaMnO 3 as a function of applied in-plane strain is observed and confirmed experimentally using high-resolution soft X-ray absorption spectroscopy (XAS) in conjunction with bulk-sensitive hard X-ray photoemission spectroscopy (HAXPES). The relevant defect states in the densities of states are identified and the vacancy content in the films quantified using the combination of first-principles theory and core-hole multiplet calculations with holistic fitting. Our findings open up a promising avenue for designing and controlling new ionically active properties and functionalities of complex transition-metal oxides via strain-induced oxygen-vacancy formation and ordering.

Published
2017
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