Researchers Succeed in Giving Topological Properties to Ordinary Metal for the First Time
This discovery points to a new route to manipulating the topological properties of materials
A group of researchers led by SATO Takafumi (Associate Professor, Department of Physics, Tohoku University), TAKAHASHI Takashi (Professor, WPI-AIMR, Tohoku University), OGUCHI Tamio (Professor, The Institute of Scientific and Industrial Research, Osaka University) and ANDO Yoichi (Professor, The Institute of Scientific and Industrial Research, Osaka University) have succeeded for the first time in giving topological properties to ordinary metal, by making a hybrid structure of topological insulator and ordinary metal.
It is well known that a topologically-protected gapless state shows up at an interface between a topological insulator and an ordinary insulator; however, the physics of the interface between a topological insulator and a metal has largely been left unexplored. The researchers have discovered a novel phenomenon termed topological proximity effect which occurs between a metallic ultrathin film and a three-dimensional topological insulator. They grew one-bilayer of bismuth metal on the three-dimensional topological-insulator material TlBiSe2, and by using spin- and angle-resolved photoemission spectroscopy, they found evidence that the topological Dirac-cone state migrates from the surface of TlBiSe2 to the attached one-bilayer Bi. Such a migration of the topological state occurs as a result of strong spin-dependent hybridization of the wave functions at the interface, which is also supported by their first-principles calculations. This discovery points to a new route to manipulating the topological properties of materials.
Figure 1. Schematic picture of Dirac cone
Figure 2. Hybrid structure of topological insulator and ordinary insulator / metal
Figure 3. Schematic picture of spin- and angle-resolved photoemission spectroscopy
Figure 4. (a) ARPES intensity plot highlighting the modulated Dirac cone. (b) Migration of topological surface states to attached Bi thin film.
To learn more about this research, please view the full research report entitled " Topological proximity effect in a topological insulator hybrid " at this page of the Nature Communicatios website.
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