Electrically Controlled Metal-Insulator Transition and Its Terahertz Applications

Texas Tech University, Lubbock TX

Investigators

Abstract

Overview: We propose to investigate dramatic changes in electronic and photonic properties of new functional devices based on the reversible metal-insulator transition (MIT) of vanadium dioxide. The electrical resistivity of VO2 changes by 4 to 5 orders. Variations in refractive index exceed 15%, giving an index contrast of greater than 3 relative to free space. This unique combination of properties motivates the study of its phase transition mechanisms, control of its properties, and development of terahertz (THz) functional components. Intellectual Merit: We will explore the fundamental physics of VO2 phase transition, particularly when driven electrically in pulsed current mode or in gate electric-field mode, and develop new functional devices for THz switching and modulation applications with the aim of reconfigurable manipulation. Through the study of phase transition mechanisms and factors to influence the transition ?speed? we will engineer the material structure to achieve abrupt ?digital? switching and controllable percolative phase transition for ?analog? modulation. The result will provide fundamental understanding of electrically controlled metal-insulator transition and promote the application of phasetransition- based materials for electronic and photonic applications. Broader Impact: Study of phase transitions will provide new opportunities to achieve innovative functional devices. These devices will exhibit unprecedented operational principles for electronic and photonic applications, in addition to fundamental scientific understanding. The proposed components will find broad applications in THz technology. The project provides excellent opportunities for interdisciplinary research education and training. Outreach efforts will attract new students, especially those from underrepresented groups, to science and engineering fields.