Purdue University scientists have successfully created an ultrapure material with unique properties that can capture new states of matter. The material so developed is governed by the mutual interactions between electrons rather than by the conventional laws of single particle physics. The team of Purdue scientists led by Michael Manfra, the William F. and Patty J. Miller Associate Professor of Physics believe that this research would see an increasing number of applications in the field of quantum computing.
Purdue professors Michael Manfra, from left, and Gabor Csathy stand next to the high-mobility gallium-arsenide molecular beam epitaxy system at the Birck Nanotechnology Center. Manfra holds a gallium-arsenide wafer on which his research team grows ultrapure gallium arsenide semiconductor crystals to observe new electron ground states that could have applications in high-speed quantum computing. Image courtesy: Purdue University
In this fundamental research, the group has singled upon a compound called Gallium Arsenide to observe upon the states of electrons which are beyond the limitations of single particle physics. The team is researching upon the some states of electrons which are nonexistent in most of the materials. However these can be observed in some of the materials like Gallium arsenide. The states about which the study is going about can be termed to be on a stage at which human understanding has not reached. In Prof. Manfra's own words, the states are on the verge of <em>what we understand and what we don't understand</em>. The electrons behave quite differently from the conventional laws of solid state physics and any other existent physical model.
The quantum computing for which this study is going on depends upon the quantum mechanical behavior of electrons. This helps in information storage and faster computation of the stored data. This will prove to be an innovation in processing speed of traditional computing. The scientists are trying to control these processes which would be helpful in calculating things which are difficult or impossible to perform on conventional computing machines. The team thus wants to tap the ability of these particles which would manipulate others' once a change is applied in one electron.
The Purdue team has designed a system called the High mobility Gallium-arsenide molecular epitaxy system (MBE) which makes high precision ultrapure semiconductor materials. The system restricts the electrons to a 2D plane and does not allow them to move in vertical direction. In brief, the electrons trapped in a 2D plane only giving it a degree of freedom in horizontal direction. For achieving this, the electrons are to be cooled to ultra low temperature, up to a range of 5 MilliKelvin or very near to absolute zero temperature. Lower temperature makes them settle and make aware of each other's presence rather than at room temperature at which all electrons are in an excited state, behaving similar to billiard balls. The electrons dance to achieve a low energy state to suit the low temperature condition.
Purdue graduate student John Watson, from left, and Michael Manfra, the William F. and Patty J. Miller Associate Professor of Physics, work with the high-mobility gallium-arsenide molecular beam epitaxy system. They are part of one of a few research teams in the world successfully creating ultrapure material that captures new states of matter. Image Courtesy: Purdue University
Another lead researcher in this study, asst Prof Gabor Csathy took up the task of measuring electron mobility. Up on constant research and study the team was able to achieve an electron mobility of 22X10<sup>6 </sup>centimeters squared per volt second. The electron mobility achieved by the group has put them in the top two of the three groups researching on the same topic. The recently presented their work on June 17 at Microsoft's prestigious Station Q summer meeting held at University of California at Santa Barbara. Based upon their preliminary results, the group received a grant of $700,000 from Department of Energy.
The project is still in its infancy and the physics involved in such type of experiments requires a high expertise materials and measurement. The other researchers in the team are research engineer Geoff Gardner, Associate professors of physics Yuli Lyanda-Geller and Leonid Rokhinson and professor of physics Gabriele Giuliani; graduate students John Watson, Nodar Samkharadze, Nianpei Deng and Sumit Mondal. Once the research is complete, the scientists would be able to control electron behavior in a semiconductor which would eventually lead to the design of a quantum computer!