March 2013 - BNC-all - ecn.purdue.edu

Condensed Matter Seminar Friday March 29th at 3:30pm in PHYS 203 - Joshua Folk
by Turner, Jaime J 27 Mar '13

27 Mar '13

Condensed Matter Seminar Friday, March 29, 2013 3:30 PM, Room 203 Physics (Refreshments 3:00 PM, Room 242) Joshua Folk [Joshua_Folk] University of British Columbia Department of Physics and Astronomy Differential thermopower spectroscopy in quantum point contacts Quantum point contacts (QPCs) are narrow constrictions between large reservoirs of two-dimensional electron gas, with conductance quantized in units of G = 2e2/h at zero magnetic field. Despite decades of investigation, many transport properties of QPCs remain mysterious, including the extra plateau commonly observed around 0.7x2e2/h (0.7structure) and a zero-bias peak in conductance on the steps between plateaus. Differential conductance is often used to study these anomalies, but this type of measurement is difficult to interpret and the underlying mechanisms are still a matter of debate. Here, we present measurements of differential thermopower (as opposed to conductance) of QPCs, both at and away from the Fermi energy. These measurements provide more direct access to the QPC transmission spectrum, and can be used to detect high-entropy states such as those characterized by spin fluctuations. We clearly observe evidence of a Kondo-screened localized state in the QPC near pinchoff, as has been predicted theoretically. For higher conductance--around 0.7 structure - the localized state gives way to a diffuse band suggestive of a high degree of spin entropy. We show comparisons to (and contrasts) with numerical simulations that as an aid to understanding the microscopic origins of QPC phenomenology.

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REMINDER: Prof. Peyman Milanfar's Seminar today at 11am in BRK 1001
by Turner, Jaime J 27 Mar '13

27 Mar '13

[cid:image001.png@01CE2AD1.BEAF3D10] Jaime Turner Birck Nanotechnology Center Purdue University 1205 West State STreet West Lafayette, IN 47907-2057 (765) 494-3509 jjturner(a)purdue.edu

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BNC e-news
by Anthrop, Heather L 25 Mar '13

25 Mar '13

Monday, March 25th Hong-yan Chen Final Exam - Graphene for Electronics Applications Birck 2001 at 10:30 am https://engineering.purdue.edu/Intranet/Groups/Schools/ECE/MinutesandMemos/… Tuesday, March 26th C.D. Mote Jr. What's Coming, Whether We Like it or Not Kurtz Atrium (ARMS) 3:30 pm https://engineering.purdue.edu/Engr/AboutUs/StrategicGrowthInitiative/Semin… Wednesday, March 27th Prof. Peyman Milanfar Data-adaptive Filtering and the State of the Art in Image Processing Brick room 1001 at 11:00 am http://www.purdue.edu/discoverypark/nanotechnology/events/view.php?id=1231 Pankaj Jha Final Exam - Cross-Plane Electrical and Thermal Transport in Oxide Metal/semiconductor Super lattices Birck room 2001 at 3:00 pm https://engineering.purdue.edu/Intranet/Groups/Schools/ECE/MinutesandMemos/… Friday, March 29th OSA - Purdue Chapter Regular Meeting Birck 1001 at 11:00 am Joseph F. Pekny FRNY room G124 at 3:30 pm https://engineering.purdue.edu/Engr/People/ptProfile?resource_id=12436 Thank you, Heather Anthrop Birck Nanotechnology Center Purdue University 1205 West State Street West Lafayette, IN 47907 (765) 494-7053

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Venture Cafe
by Anthrop, Heather L 25 Mar '13

25 Mar '13

The Venture Café located in Burton Morgan will be closed today, Monday, March 25th. Thank you, Heather Anthrop Birck Nanotechnology Center Purdue University 1205 West State Street West Lafayette, IN 47907 (765) 494-7053

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FW: Discovery Lecture Series--March 21 at 3:00 p.m.
by Turner, Jaime J 21 Mar '13

21 Mar '13

REMINDER: Please join us at 3:00 p.m. in Burton D. Morgan Center for Entrepreneurship, room 121 for Dr. Ellenbogen's Discovery Lecture Series presentation on "Integrated Nanosystems for Ultra-Miniaturized Computers . . .And More." [cid:image001.jpg@01CE1414.618D8890]

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Prof. Lawrence Carin Seminar Today at 11:00am in BRK 1001
by Turner, Jaime J 19 Mar '13

19 Mar '13

[cid:image001.png@01CE2487.0AC7E360] Jaime Turner Birck Nanotechnology Center Purdue University 1205 West State STreet West Lafayette, IN 47907-2057 (765) 494-3509 jjturner(a)purdue.edu

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Nano materials seminar on Monday, March 18
by Anthrop, Heather L 15 Mar '13

15 Mar '13

Monday, March 18, 2013 3:30 p.m. 2-425 Lilly (3:15 pm for pre-visiting, coffee, refreshments) Some Investigations of Metal Oxide Nanomaterials and Terrestrial Organisms Patricia Holden University of California, Santa Barbara [cid:image002.jpg@01CE2181.C896B1E0]Manufactured nanomaterials (MNMs) are increasingly produced and used, and therefore are entering the environment. Still, little is known about potential environmental effects and therefore how to design MNMs to safeguard the environment. Soils are expected to be accumulators of MNMs, mainly in the U.S. from biosolids land disposal practices. While some MNMs may not be bioavailable in soil, other MNM chemistries may result in soil microbial and plant exposure. We have been studying bacterial population and community level effects of some common metal oxide MNMs. Our collaborators have studied plant population effects with similar materials. Results from both types of experiments will be discussed. Then, a greenhouse experiment with soybean in organic farm soil will be presented, where similar MNMs were examined for their effects on plants, microbes, and plant-microbe interactions in a more agriculturally-realistic context. The results suggest potential effects of these MNMs long term, if there is buildup in soil. A broader discussion is then suggested about contexts, and controls, in conducting such experiments. The work presented is representative of results in the University of California, Center for Environmental Implications of Nanotechnology, within which Holden is a member and leader of Theme 4 "Terrestrial Ecosystem Impacts".

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BNC E-news
by Anthrop, Heather L 15 Mar '13

15 Mar '13

Tuesday, March 19th Integrated Imaging Seminar Prof. Lawrence Carin Birck 1001 at 11:00 am http://www.purdue.edu/discoverypark/nanotechnology/events/view.php?id=1230 Distinguished Seminar Series C.D. Mote Jr. What's Coming, Whether We Like it or Not ARMS, Kurz Atrium at 3:30 pm https://engineering.purdue.edu/Engr/AboutUs/StrategicGrowthInitiative/Semin… Thursday, March 21st Integrated Nanosystems for Ultra-Miniaturized Computers ...and more Dr. James C Ellenbogen Morgan room 121 at 3:00 pm http://www.purdue.edu/discoverypark/dls/index.html Friday, March 22nd OSA - Purdue Chapter Meeting Birck 1001 at 11:00 am Ravi Pramod Kumar Vedula Final Exam Predictive Atomistic Modeling of Electronic Properties in Realistic Nanoscale Devices: A multiscale Modeling Approach Birck room 1001 at 3:00 pm https://engineering.purdue.edu/Intranet/Groups/Schools/ECE/MinutesandMemos/… Thank you, Heather Anthrop Birck Nanotechnology Center Purdue University 1205 West State Street West Lafayette, IN 47907 (765) 494-7053

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Discovery Lecture Series--March 21 at 3:00 p.m.
by Anthrop, Heather L 13 Mar '13

13 Mar '13

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Date Change: Dr. Jan Mol's Seminar "Acceptor Based Qubits in Silicon"
by Buckles, Amanda L 12 Mar '13

12 Mar '13

Please be aware, this seminar has been moved to Thursday, March 14, 2013. Acceptor based qubits in silicon Thursday, March 14, 2013 11:00AM Burton Morgan Building, Room 129 Dr. Jan Mol Centre for Quantum Computation and Communication Technology University of New South Wales, Sydney, Australia Systems with spin-orbit interaction have significant potential for solid-state quantum computation. Coupling between the orbital angular momentum and the spin in the valence band of silicon opens the possibility for rapid all-electrical manipulation of an acceptor-bound spin-orbit state, while selection rules can provide a qubit basis that is protected from decoherence by time-reversal symmetry. Building on the seminal work of Kane, I will present a design for an acceptor-based quantum computer where the transitions between the working levels of the qubit can be switched on and off by manipulating the acceptor wave function. The crucial parameter here is the interface-induced energy splitting between the two Kramers doublets that make up the ground state of the undisturbed acceptor wave function. Based on fully atomistic tight binding simulations and low-temperature scanning tunnelling spectroscopy interface-split Kramers doublets of individual boron acceptors near a silicon surface are visualised and identified. The electron temperature in the sample is used as a reference to directly determine the energy splitting between the Kramers doublets as a function of acceptor depth which is found to be in good agreement with calculations. Finally, the observed energy splitting of ~4 meV effectively protects acceptor-based qubit from decoherence. About the Speaker: After graduating with a Master's Degree in Applied Physics at the Delft University of Technology in the Netherlands I obtained my PhD Degree in Delft in 2012 studying Single Atom Electronics in the group of Prof. dr. Sven Rogge. During my time as a PhD student I moved to Sydney, Australia where I am currently working as a Postdoctoral Fellow at the Centre for Quantum Computation and Communication Technology at the University of New South Wales. My research focusses on studying single dopant atoms in silicon using Scanning Tunneling Spectroscopy with the emphasis on using dopants as building blocks for quantum computation. Best Regards, Amanda Buckles Operations Manager Network for Computational Nanotechnology Purdue University Phone: (765)496-3770 albuckles(a)purdue.edu<mailto:albuckles@purdue.edu> [cid:image001.jpg@01CE1EF5.5FFF7100]<http://nanohub.org/>

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