Negative Capacitance in Organic Ferroelectrics
Comprehensive Exam
3:00 pm –
4:00 pm
Jorgensen Hall
Contact:
Physics Department, paoffice@unl.edu
Yifan Yuan will be presenting their comprehensive exam topic, “Negative Capacitance in Organic Ferroelectrics”
Zoom Meeting: https://unl.zoom.us/j/9764021777 (Meeting ID: 976 402 1777)
ABSTRACT:
The capacitor is a critical device in electronics that stores charges as voltage increases due to its positive capacitance. However, a capacitor with a negative capacitance would charge spontaneously. Although global capacitance is always positive, local negative capacitance (NC) may occur in certain situations. NC behaviors can lead to capacitance enhancement, enhancement of interface voltage, and enable the field-effect transistor to break through its Boltzmann tyranny. However, a thorough understanding of its physical nature remains controversial and elusive, especially in organic ferroelectrics, thus far. In this proposal, we discuss the mechanisms of NC behaviors for ferroelectrics, the origins of polarization in organic ferroelectrics compared to inorganic ferroelectrics, and some common models for the kinetics of polarization switching in the context of domain nucleation and growth. We also review recent progress in the research for transient NC behaviors and highlight many challenges for understanding their physical processes. At last, we propose to investigate the transient NC behaviors in organic ferroelectric materials, and to explore the relationship between polarization switching kinetics and transient NC responses.
Zoom Meeting: https://unl.zoom.us/j/9764021777 (Meeting ID: 976 402 1777)
ABSTRACT:
The capacitor is a critical device in electronics that stores charges as voltage increases due to its positive capacitance. However, a capacitor with a negative capacitance would charge spontaneously. Although global capacitance is always positive, local negative capacitance (NC) may occur in certain situations. NC behaviors can lead to capacitance enhancement, enhancement of interface voltage, and enable the field-effect transistor to break through its Boltzmann tyranny. However, a thorough understanding of its physical nature remains controversial and elusive, especially in organic ferroelectrics, thus far. In this proposal, we discuss the mechanisms of NC behaviors for ferroelectrics, the origins of polarization in organic ferroelectrics compared to inorganic ferroelectrics, and some common models for the kinetics of polarization switching in the context of domain nucleation and growth. We also review recent progress in the research for transient NC behaviors and highlight many challenges for understanding their physical processes. At last, we propose to investigate the transient NC behaviors in organic ferroelectric materials, and to explore the relationship between polarization switching kinetics and transient NC responses.