Weak antilocalization and electron-electron interactions in topological insulator BixTey films deposited by sputtering on Si(100)

• Topological insulators (TIs) which exhibit spin-momentum locking constitute an interesting class of quantum materials. In this paper, we present a systematic method to prepare BixTey films having tunable Bi/Te composition by employing a direct current (DC) cosputtering technique. Films of three different Te compositions, namely, the Te-deficient (BiTe), Te-stoichiometric (Bi2Te3), and Te-excessive (BiTe3) phases, have been investigated in detail by performing the measurements of their temperature-dependent resistivity and in-plane and out-of-plane magnetoresistance responses. Clear evidence of the presence of a weak antilocalization effect and electron-electron interaction are observed in all three films having different phases of Bi-Te system. Using the Hikami-Larkin-Nagaoka and Al'tshuler-Aronov models, the topological characteristics have been evidently distinguished in these three different phases of BixTey. The analysis of the fitting of the experimental magnetotransport data is performed to quantitatively determine the critical model parameters, viz., phase coherence length (l(phi)), surface state penetration depth (lambda), coherency factor (alpha), and dephasing parameter (p) through which Berry phase and dimensionality of transport channels can be estimated. In this paper, we reveal a systematic correlation between the composition of the BixTey films and their topological properties. The parameter kappa, slope of temperature dependence of conductivity correction, is studied at different magnetic fields, which suggested that the Testoichiometric sample shows better features of topological properties than the Te-deficient and Te-excessive samples. These experimental observations are supplemented by first-principles calculations. Additionally, we demonstrate that TIs can be grown by the sputtering technique as is desired for realizing industrial applications.

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NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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