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Local Structure and Bonding of Transition Metal Dopants in Bi2Se3 Topological Insulator Thin Films

DOI: 10.1021/jp511713s DOI Help

Authors: Adriana Figueroa-garcia (Diamond Light Source) , Gerrit Van Der Laan (Diamond Light Source) , Liam Collins-mcintyre (University of Oxford) , Giannantonio Cibin (Diamond Light Source) , Andrew Dent (Diamond Light Source Ltd) , Thorsten Hesjedal (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Journal Of Physical Chemistry C , VOL 119 (30) , PAGES 17344 - 17351

State: Published (Approved)
Published: July 2015
Diamond Proposal Number(s): 11060 , 9178 , 11119

Abstract: Transition metal (TM) doped topological insulators have been the focus of many recent studies since they exhibit exotic quantum and magneto-electric effects, and offer the prospect of potential applications in spintronic devices. Here we report a systematic study of the local electronic and structural environment using X-ray absorption fine structure (XAFS) in TM (=Cr, Mn, and Fe) doped Bi2Se3 thin films grown by molecular beam epitaxy. Analysis of the TM K-edge XAFS reveals a divalent character for Cr, Mn, and Fe when substituting Bi in the films, despite the trivalent character of the Bi. All dopants occupy octahedral sites in the Bi2Se3 lattice, which agrees with substitutional incorporation onto the Bi sites. With the incorporation of TM dopants a local structural relaxation of the Bi2Se3 lattice is observed, which strengthens the covalent character of the TM−Se bond. The presence of additional phases and interstitial incorporation for the Mn and Fe dopants is also observed, even at low concentrations.

Subject Areas: Chemistry, Physics, Materials

Instruments: B18-Core EXAFS

Other Facilities: No

Added On: 08/08/2015 19:45

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