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Wednesday, 21 January 2015

New Molecular Beam Epitaxy deposition equipment at the ICN2

The new equipment allows the manufacturing of topological insulators, among other materials, and the possibility to study their properties when submitted to different conditions. The installation of the MBE also means a new way of collaboration among ICN2 Groups thanks to the new Severo Ochoa positions.

A new molecular beam epitaxy (MBE) equipment has been installed at the Institut Catala de Nanociencia i Nanotecnologia (ICN2). This acquisition has been led by ICREA Research Prof. Sergio Valenzuela, Group Leader of the Physics and Engineering of Nanodevices Group, and it has been possible thanks to his European Research Council Starting Grant.

MBE is a method of depositing single crystals mostly used to manufacture semiconductor devices. The process consists in heating some kind of solids in a slow way until they begin to sublime. The steam then condenses over a wafer and the crystals grow, layer by layer. All these take place in vacuum conditions to guarantee the maximum purity of the materials.

Prof. Valenzuela’s group mainly uses this technique to create topological insulators. These materials are characterized for allowing electrical current in their surface but being insulators in the interior. They also stand out because they can be reduced to a nanoscale level without losing conductive power: the surface states do not suffer any change when modifying the size. These properties make them materials with great potential for the developing of new applications in many fields, for example spintronics. Some of them could have an impact in the development of non-volatile configuration memories, fastest circuits or magnetic memories, among others.

Watch the time-lapse installation video:

At ICN2, researchers are using the new equipment not only to create materials but also to study their surface conducting states when they are submitted to different surface conditions, such as temperature changes or interaction with other materials placed over the insulator. Two Severo Ochoa students will be co-working with Prof. Valenzuela’s Group using the new equipment to develop their researches. One of them, shared with the Phononic and Photonic Nanostructures Group, will study thermoelectric properties of topological insulators. The other one, shared with the Atomic Manipulation and Spectroscopy Group, will study these materials when submitted to surface changes induced by the deposition of (magnetic) molecules. The research carried out with the new equipment will also estimulate further interaction with ICN2 theoretical groups, such as the ones led by CSIC Prof Pablo Ordejón and ICREA Prof Stephan Roche, who will supervise Severo Ochoa funded students and postdocs focused on the exotic properties of topological insulators.