Physics Colloquium: Dr. Garnett Bryant

Wednesday, December 05, 2018, 04:00pm

Dr. Garnett Bryant, NIST

*"Atom-based solid-state electronics, photonics, and many-body physics: Nanotechnology goes atomic scale"*

Coffee and cookies will be served at 3:45pm in RLM 4.102

**Abstract:** Nanotechnology has been ubiquitous in electronics, photonics and quantum devices. Quantum dots and nanocrystals have proven to be excellent single, quantum photon sources and have been used in single-electron transistors. Metal nanoparticle plasmons generate highly localized intense fields ideal for sensing, local heating and coupling to quantum emitters. Plasmons in nanoscale structures can display quantum interference, just as photons do, even though plasmons rapidly decohere. Quantum dots are often called “artificial atoms” because of their discrete electronic structure. However, they still contain tens of thousands of atoms. Recently, solid-state structures which are atomic scale in one dimension, such as graphene and 2D layers of transition metal dichalcogenides, have shown strong electronics, plasmonic and photonic response. Now solid-state structures that are atomic-scale in two dimensions, such as chains of atoms on a surface, and in all three dimensions, such as dopant atoms in Si and defects in 2D materials, show great potential as photonic, electronic and quantum structures. In this talk, I will describe how dopant atoms can be positioned in Si with atomic scale precision to form two dimensional planes of dopants (atomic scale in one dimension), wires of dopants (atomic-scale in two dimensions) and ordered collections of a few dopants (atomic scale in all dimensions). To illustrate the challenges in making these structures in the solid state, I will highlight the work that we needed to do at NIST to overcome these challenges. This opens up the possibility of making atomic-scale solid-state structures on demand. These dopant based structures in Si have drawn great interest for quantum information because the individual dopants are excellent candidate qubits, easily integrable with traditional Si electronics. I will describe some of the work to date in realizing both single-electronic transistors, and now, single and two-qubit structures. I will then point to some of the photonic and metrology applications that might be possible with these devices. Moreover, these atomic scale structures could be used to simulate complicated many-body Hamiltonians that are currently very difficult to solve. I will close by showing some calculations for few atom structures to illustrate the physics of how plasmons become quantized and the many body physics that can be revealed in small, few-atom structures.

Location: John A. Wheeler Lecture Hall (RLM 4.102)