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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:3
UID:UW-Physics-Event-5152
DTSTART:20191107T170000Z
DURATION:PT1H0M0S
DTSTAMP:20260414T195437Z
LAST-MODIFIED:20191104T182242Z
LOCATION:5310 Chamberlin Hall
SUMMARY:Atom-based Silicon Devices for Quantum Technologies\, R. G. He
 rb Condensed Matter Seminar\, Dr. Rick Silver\, NIST
DESCRIPTION:NIST is using atomically precise fabrication to develop el
 ectronic devices for use in quantum information processing\, quantum m
 aterials research and quantum sensing.  We are using hydrogen-based sc
 anning probe lithography to enable deterministic placement of individu
 al dopant atoms with atomically aligned contacts and gates to fabricat
 e single electron transistors\, single atom transistors\, few-donor/qu
 antum dot devices for spin manipulation\, and arrayed few-donor device
 s for quantum materials and analog quantum simulation research.  We ha
 ve developed robust lithography\, device relocation\, and contact proc
 esses that enable routine electrical measurement of atomically precise
  devices with an emphasis on atom-scale control of the device geometry
 .  
\n
\nIn addition to our fabrication technology\, I will discuss th
 e characterization of atomic-scale tunnel junctions and single electro
 n transistors that demonstrate stable coulomb blockade oscillations wi
 th charge offset drift of 0.007e per day. I will present measurements 
 of tunnel coupling in single electron transistors and donor-dot device
 s where the tunnel gap is controlled at the atomic scale as well as me
 asurements and modeling of single and few atom transistors that displa
 y large electron addition energies\, consistent with single or few dop
 ant atom charging energies. 
\n
\nWe have recently extended our STM-pa
 tterning to fabricate coupled arrays of few atom clusters having multi
 ple donors per dot\, including a functional 3×3 quantum dot array dev
 ice.  Using the Si(100)2x1 surface reconstruction as an atomic ruler\,
  we design the separation between nearest neighbor dots to be in the r
 egime from weakly coupled to strongly coupled. We are analyzing the tu
 nnel couplings and energy spectra in individual dots versus across an 
 array of coupled dots to explore the rich physics of dot-arrays. 
\n
\
 nBio: Richard Silver is a physicist leading the atom-based silicon qua
 ntum electronics effort at NIST.  His research focusses on fabrication
 \, design\, and measurement of atom-based Si structures that rely on s
 ingle or few atoms\, precisely placed within an epitaxial silicon envi
 ronment for solid state quantum computing and analog quantum simulatio
 n. He received his bachelors in physics from the University of Califor
 nia at Berkeley and his PhD in physics from University of Texas at Aus
 tin. He is an adjunct professor with the physics department at the Uni
 versity of Maryland\, College Park.
\n
URL:https://www.physics.wisc.edu/events/?id=5152
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