2 ms·

Quantum interference enhances the performance of single-molecule transistors

2 points by westurner 3y ago

westurner 3y ago
"Transistor Takes Advantage of Quantum Interference" (2024) https://spectrum.ieee.org/amp/quantum-interference-transistor-2667620631 https://spectrum.ieee.org/amp/quantum-interference-transisto... : "Quantum interference enhances the performance of single-molecule transistors" (2014) https://www.nature.com/articles/s41565-024-01633-1 https://www.nature.com/articles/s41565-024-01633-1 : > Abstract: Quantum effects in nanoscale electronic devices promise to lead to new types of functionality not achievable using classical electronic components. However, quantum behaviour also presents an unresolved challenge facing electronics at the few-nanometre scale: resistive channels start leaking owing to quantum tunnelling. This affects the performance of nanoscale transistors, with direct source–drain tunnelling degrading switching ratios and subthreshold swings, and ultimately limiting operating frequency due to increased static power dissipation. The usual strategy to mitigate quantum effects has been to increase device complexity, but theory shows that if quantum effects can be exploited in molecular-scale electronics, this could provide a route to lower energy consumption and boost device performance. Here we demonstrate these effects experimentally, showing how the performance of molecular transistors is improved when the resistive channel contains two destructively interfering waves. We use a zinc-porphyrin coupled to graphene electrodes in a three-terminal transistor to demonstrate a >10^4 conductance-switching ratio, a subthreshold swing at the thermionic limit, a >7 kHz operating frequency and stability over >10^5 cycles. We fully map the anti-resonance interference features in conductance, reproduce the behaviour by density functional theory calculations and trace back the high performance to the coupling between molecular orbitals and graphene edge states. These results demonstrate how the quantum nature of electron transmission at the nanoscale can enhance, rather than degrade, device performance, and highlight directions for future development of miniaturized electronics.
- westurner 3y ago
  Having remembered an article about superabsorption increasing battery charge rate, I wondered whether there is superradiance with electrons, and there is! : "Superradiance and Subradiance due to Quantum Interference of Entangled Free Electrons" (2021) https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.060403 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.12... > [...] Our findings suggest that light emission can be sensitive to the explicit quantum state of the emitting matter wave and possibly serve as a nondestructive measurement scheme for measuring the quantum state of many-body systems.
  - westurner 3y ago
    > an article about superabsorption increasing battery charge rate "Physicists steer chemical reactions by magnetic fields and quantum interference" https://news.ycombinator.com/item?id=30647086 https://news.ycombinator.com/item?id=30647086 : "Superabsorption in an organic microcavity: Toward a quantum battery" (2022) https://www.science.org/doi/10.1126/sciadv.abk3160 https://www.science.org/doi/10.1126/sciadv.abk3160 : > [...] Our work opens future opportunities for harnessing collective effects in light-matter coupling for nanoscale energy capture, storage, and transport technologies.

2 points by westurner 3y ago

"Transistor Takes Advantage of Quantum Interference" (2024) https://spectrum.ieee.org/amp/quantum-interference-transistor-2667620631 https://spectrum.ieee.org/amp/quantum-interference-transisto... : "Quantum interference enhances the performance of single-molecule transistors" (2014) https://www.nature.com/articles/s41565-024-01633-1 https://www.nature.com/articles/s41565-024-01633-1 : > Abstract: Quantum effects in nanoscale electronic devices promise to lead to new types of functionality not achievable using classical electronic components. However, quantum behaviour also presents an unresolved challenge facing electronics at the few-nanometre scale: resistive channels start leaking owing to quantum tunnelling. This affects the performance of nanoscale transistors, with direct source–drain tunnelling degrading switching ratios and subthreshold swings, and ultimately limiting operating frequency due to increased static power dissipation. The usual strategy to mitigate quantum effects has been to increase device complexity, but theory shows that if quantum effects can be exploited in molecular-scale electronics, this could provide a route to lower energy consumption and boost device performance. Here we demonstrate these effects experimentally, showing how the performance of molecular transistors is improved when the resistive channel contains two destructively interfering waves. We use a zinc-porphyrin coupled to graphene electrodes in a three-terminal transistor to demonstrate a >10^4 conductance-switching ratio, a subthreshold swing at the thermionic limit, a >7 kHz operating frequency and stability over >10^5 cycles. We fully map the anti-resonance interference features in conductance, reproduce the behaviour by density functional theory calculations and trace back the high performance to the coupling between molecular orbitals and graphene edge states. These results demonstrate how the quantum nature of electron transmission at the nanoscale can enhance, rather than degrade, device performance, and highlight directions for future development of miniaturized electronics.

westurner 3y ago
Having remembered an article about superabsorption increasing battery charge rate, I wondered whether there is superradiance with electrons, and there is! : "Superradiance and Subradiance due to Quantum Interference of Entangled Free Electrons" (2021) https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.060403 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.12... > [...] Our findings suggest that light emission can be sensitive to the explicit quantum state of the emitting matter wave and possibly serve as a nondestructive measurement scheme for measuring the quantum state of many-body systems.
- westurner 3y ago
  > an article about superabsorption increasing battery charge rate "Physicists steer chemical reactions by magnetic fields and quantum interference" https://news.ycombinator.com/item?id=30647086 https://news.ycombinator.com/item?id=30647086 : "Superabsorption in an organic microcavity: Toward a quantum battery" (2022) https://www.science.org/doi/10.1126/sciadv.abk3160 https://www.science.org/doi/10.1126/sciadv.abk3160 : > [...] Our work opens future opportunities for harnessing collective effects in light-matter coupling for nanoscale energy capture, storage, and transport technologies.