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Physics and Astronomy Condensed Matter Seminar

Plastic transistors: Simple solutions to their complex problems

Plastic semiconductors incorporated into transistors have shown enormous potential for low-cost, flexible, printable electronics and bioelectronics. In my talk, I will discuss their history, operating mechanisms, and potential applications. I will highlight key challenges to these applications, and discuss some of the approaches I've taken to overcome them. I will show how these simple solutions can work towards the broad realization of organic transistors.

Date:
Location:
Chemistry-Physics Bldg. Room 303
Tags/Keywords:

Plastic transistors: Simple solutions to their complex problems

Plastic semiconductors incorporated into transistors have shown enormous potential for low-cost, flexible, printable electronics and bioelectronics. In my talk, I will discuss their history, operating mechanisms, and potential applications. I will highlight key challenges to these applications, and discuss some of the approaches I've taken to overcome them. I will show how these simple solutions can work towards the broad realization of organic transistors.

Date:
Location:
Chemistry-Physics Bldg. Room 303
Tags/Keywords:

Carbon Based Nano Electromechanics: Physics and Applications

Carbon Based Nano Electromechanics: Physics and Applications
 
Sang Wook Lee
 
Department of Physics, Ewha Womans University, Seoul, 03760, Korea
 
In this presentation, physical properties and possible applications of carbon based nano electro-mechanical devices
(NEMS) will be introduced. Our research started from carbon nanotube based nano electro-mechanical relay
structure and expanded to graphene-based xylophone and drum like devices. Micro contact transfer method is
applied to realize the suspended nano structures with various electrodes under the nano materials. Recently
developed pick-up and transfer technique made us possible to fabricate various stacking and suspended nano
structures. After introducing some interesting physical properties, such as basic mechanical switching and
resonance behaviour and light emission of suspended graphene structures, possible application of carbon based
nano electro-mechanical devices will be suggested. Graphene based ultra-sensitive mass detector will be suggested
for one of the promising applications of our devices and our recent research project on single protein sequencing
using graphene-based mass detector will be introduced at the end of presentation.
Date:
Location:
Chemistry-Physics Bldg. Room 179
Tags/Keywords:

Carbon Based Nano Electromechanics: Physics and Applications

Carbon Based Nano Electromechanics: Physics and Applications
 
Sang Wook Lee
 
Department of Physics, Ewha Womans University, Seoul, 03760, Korea
 
In this presentation, physical properties and possible applications of carbon based nano electro-mechanical devices
(NEMS) will be introduced. Our research started from carbon nanotube based nano electro-mechanical relay
structure and expanded to graphene-based xylophone and drum like devices. Micro contact transfer method is
applied to realize the suspended nano structures with various electrodes under the nano materials. Recently
developed pick-up and transfer technique made us possible to fabricate various stacking and suspended nano
structures. After introducing some interesting physical properties, such as basic mechanical switching and
resonance behaviour and light emission of suspended graphene structures, possible application of carbon based
nano electro-mechanical devices will be suggested. Graphene based ultra-sensitive mass detector will be suggested
for one of the promising applications of our devices and our recent research project on single protein sequencing
using graphene-based mass detector will be introduced at the end of presentation.
Date:
Location:
Chemistry-Physics Bldg. Room 179
Tags/Keywords:

Detection of 5/2 phases

Dr. Ankur Das

Postdoctoral Research Associate

Weizmann Institute of Science

Rehovot, Israel

 

Title: Detection of 5/2 phases

Abstract: The phases of the \nu=5/2 state have been shown to be very elusive but one of the most interesting ones as it is proposed to contain Majorana modes with non-abelian statistics. There is more than one candidate for the non-abelian state and among that three are the most promising ones namely pfaffian, anti-pfaffian, and particle-hole symmetric pfaffian. Quite a few experiments later the issue has not been settled. Previous efforts proposed methods to distinguish the candidates including the proposals where the order can be determined by measuring both thermal conductances and shot noise on the same device [Park et al. PRL 125, 157702 (2020)] or by only measuring the unequilibrated electrical conductance [Yutushui et al. PRL 128, 016401 (2022)]. To avoid some of the experimental challenges and limitations of the proposals including the above-mentioned ones we propose a new device made out of interfaces of the \nu=5/2 state and Abelian states. We propose to measure electrical shot noise to resolve among these states.

Date:
-
Location:
TBA
Tags/Keywords:

Detection of 5/2 phases

Dr. Ankur Das

Postdoctoral Research Associate

Weizmann Institute of Science

Rehovot, Israel

 

Title: Detection of 5/2 phases

Abstract: The phases of the \nu=5/2 state have been shown to be very elusive but one of the most interesting ones as it is proposed to contain Majorana modes with non-abelian statistics. There is more than one candidate for the non-abelian state and among that three are the most promising ones namely pfaffian, anti-pfaffian, and particle-hole symmetric pfaffian. Quite a few experiments later the issue has not been settled. Previous efforts proposed methods to distinguish the candidates including the proposals where the order can be determined by measuring both thermal conductances and shot noise on the same device [Park et al. PRL 125, 157702 (2020)] or by only measuring the unequilibrated electrical conductance [Yutushui et al. PRL 128, 016401 (2022)]. To avoid some of the experimental challenges and limitations of the proposals including the above-mentioned ones we propose a new device made out of interfaces of the \nu=5/2 state and Abelian states. We propose to measure electrical shot noise to resolve among these states.

Date:
-
Location:
TBA
Tags/Keywords:

Superfluid Helium Electromechanics

Professor John Davis

Associate Professor

University of Alberta

Department of Physics

 

Title:  Superfluid Helium Electromechanics

Abstract: Liquid helium posses many properties that make it an attractive medium for studies of mechanical systems in the quantum regime, such as low mechanical and dielectric losses.  The flip side of this is to imagine using optomechanics or electromechanics to revisit the novel physics of superfluid helium, including bosonic helium-4 and fermionic helium-3.  In particular, when spatially restricted in one dimension, helium superfluids are expected to demonstrate quasi-two dimensional behavior with qualitatively different physics than in three dimensions.  By using nanofabrication techniques to both confine the helium and provide an electromechanical detection scheme, we are beginning the journey of studying such two-dimensional superfluids.

Date:
-
Location:
Zoom
Tags/Keywords:

Superfluid Helium Electromechanics

Professor John Davis

Associate Professor

University of Alberta

Department of Physics

 

Title:  Superfluid Helium Electromechanics

Abstract: Liquid helium posses many properties that make it an attractive medium for studies of mechanical systems in the quantum regime, such as low mechanical and dielectric losses.  The flip side of this is to imagine using optomechanics or electromechanics to revisit the novel physics of superfluid helium, including bosonic helium-4 and fermionic helium-3.  In particular, when spatially restricted in one dimension, helium superfluids are expected to demonstrate quasi-two dimensional behavior with qualitatively different physics than in three dimensions.  By using nanofabrication techniques to both confine the helium and provide an electromechanical detection scheme, we are beginning the journey of studying such two-dimensional superfluids.

Date:
-
Location:
Zoom
Tags/Keywords:

TBA

Dr. Allen Scheie

Postdoctoral Research Associate

Oak Ridge National Laboratory

Neutron Scattering Division

Title: Witnessing entanglement in quantum magnets using neutron scattering

Abstract: In this talk I show how information about solid state quantum entanglement can be extracted from magnetic neutron scattering using model-independent techniques. Using the 1D spin chain KCuF3, we examine three entanglement witnesses applicable to neutron scattering: one tangle, two tangle, and Quantum Fisher Information (QFI). We find that QFI is the most experimentally robust, giving good agreement between theory and experiment over all measured temperatures, and witnessing multipartite entanglement up to 75 K. We then apply the entanglement witnesses to the 2D triangular lattice KYbSe2, showing the presence of appreciable entanglement in the low temperature phase. We then use diffuse scattering fits, heat capacity comparisons, and nonlinear spin wave fits to demonstrate that KYbSe2 is proximate to a quantum spin liquid. We thus provide a rigorous route to studying and understanding highly entangled quantum phases.

Date:
-
Location:
Blazer 339
Tags/Keywords:

TBA

Dr. Allen Scheie

Postdoctoral Research Associate

Oak Ridge National Laboratory

Neutron Scattering Division

Title: Witnessing entanglement in quantum magnets using neutron scattering

Abstract: In this talk I show how information about solid state quantum entanglement can be extracted from magnetic neutron scattering using model-independent techniques. Using the 1D spin chain KCuF3, we examine three entanglement witnesses applicable to neutron scattering: one tangle, two tangle, and Quantum Fisher Information (QFI). We find that QFI is the most experimentally robust, giving good agreement between theory and experiment over all measured temperatures, and witnessing multipartite entanglement up to 75 K. We then apply the entanglement witnesses to the 2D triangular lattice KYbSe2, showing the presence of appreciable entanglement in the low temperature phase. We then use diffuse scattering fits, heat capacity comparisons, and nonlinear spin wave fits to demonstrate that KYbSe2 is proximate to a quantum spin liquid. We thus provide a rigorous route to studying and understanding highly entangled quantum phases.

Date:
-
Location:
Blazer 339
Tags/Keywords: