Research

Overview of QNS

The Center for Quantum Nano Science (QNS) . Quantum nanoscience is a novel research field at the intersection of quantum and nanoscience. Quantum science studies the quantum mechanical properties of matter, whereas molecular nanoscience, as we call it, focuses on materials at the atomic scale. Hence one focus of QNS is the investigation of the quantum behavior of atoms and molecules on surfaces. In this endeavor, we employ specialized tools that allow us to see and touch atoms and move them into desired atomic positions. This allows us to build engineered structures consisting of several atoms, which often have surprising and sometimes useful properties.

QNS focuses on a basic exploration of our world on the atomic scale with an eye towards harnessing these quantum behaviors for high-density data storage and quantum computation.

 
 

Recent Results

Quantum Decoherence

Using advanced and novel techniques, QNS scientists identified which mechanisms destroy the quantum properties of individual atoms by manipulating the magnetic state of a single iron atom on a thin insulator. Using a Scanning Tunneling Microscope, which utilizes an atomically sharp metal tip, they were able to precisely image individual iron atoms and measure and control the time that the iron atom can maintain its quantum behavior.

One Atom Bit

Utilizing Scanning Tunnelling Microscope

One bit of digital information can now be successfully stored in an individual atom, according to a study just published in Nature. Current commercially-available magnetic memory devices require approximately one million atoms to do the same.

Andreas Heinrich, newly appointed Director of the Center for Quantum Nanoscience, within the Institute of Basic Science (IBS, South Korea), led the research effort that made this discovery at IBM Almaden Research Center (USA). This result is a breakthrough in the miniaturization of storage media and has the potential to serve as a basis for quantum computing.

A Quantum Sensor Made from Individual Iron Atoms

QNS researchers, in collaboration with a team of IBM researchers in the USA have succeeded in using individual iron atoms as quantum sensors. Using this sensor, they were able to measure the small magnetic field created by neighboring magnetic atoms, an effect that was previously not measurable in scanning tunneling microscopy.

This work is the first application of a recent breakthrough invention of the same team, which demonstrated electron spin resonance – a quantum mechanical measurement of single spins – in the STM. “We believe that this quantum sensor can be used to measure the spins in complex molecules with atomic-scale spatial resolution, sort of like a nano-GPS”, suggests Taeyoung Choi, first author of the recent study.

Scanning Tunneling Microscope

The Scanning Tunneling Microscope is a conceptually rather simple tool that has amazing capabilities. It ‘images’ the surface of a material – here labelled as sample – by bringing a really sharp metal needle – here labelled as tip – very close. The actual distance between the last atom on the tip and the atoms on the surface of the sample is about one nanometer, which corresponds to only about 4 atom spacings in most solid materials. At this close approach, electrons can jump from tip to sample and from sample to tip by using the quantum mechanical effect called tunneling. When a small voltage is applied between tip and sample, a current flows, which we measure. This current is extremely sensitive to the distance: for example it become 10 times smaller when the distance is increased from 1 to 1.1nm.

At QNS, we are using STM not only to image surfaces with atomic resolution but also to move the atoms into desired configurations. This enable us to engineer these nanostructures and then build them with ultimate precision. Finally, we use very high resolution spectroscopic measurements to investigate the electronic and magnetic properties of such systems.
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