Versatile electronic states in epitaxial thin films of (Sn-Pb-In)Te: from topological crystalline insulator and polar semimetal to superconductor

Abstract

Epitaxial thin films of (Sn${}_x$Pb${}_{1-x}$)${}_{1-y}$In${}_y$Te were successfully grown by molecular-beam-epitaxy (MBE) in a broad range of compositions (0 $\le$ x $\le$ 1, 0 $\le$ y $\le$ 0.23). We investigated electronic phases of the films by the measurements of electrical transport and optical second harmonic generation. In this system, one can control the inversion of band gap, the electric polarization that breaks the inversion symmetry, and the Fermi level position by tuning the Pb/Sn ratio and In composition. A plethora of topological electronic phases are expected to emerge, such as topological crystalline insulator, topological semimetal, and superconductivity. For the samples with large Sn compositions (x > 0.5), hole density increases with In composition (y), which results in the appearance of superconductivity. On the other hand, for those with small Sn compositions (x < 0.5), increase in In composition reduces the hole density and changes the carrier type from p-type to n-type. In a narrow region centered at (x, y) = (0.16, 0.07) where the n-type carriers are slightly doped, charge transport with high mobility exceeding 5,000 cm${}^2$V${}^{-1}$s${}^{-1}$ shows up, representing the possible semimetal states. In those samples, the optical second harmonic generation measurement shows the breaking of inversion symmetry along the out-of-plane [111] direction, which ensures the presence of polar semimetal state. The thin films of (Sn${}_x$Pb${}_{1-x}$)${}_{1-y}$In${}_y$Te materials systems with a variety of electronic states would become a promising materials platform for the exploration of novel quantum phenomena.

References in corpus (24)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Valley polarization in MoS2 monolayers by optical pumping
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Topological Crystalline Insulators in the SnTe Material Class
• Experimental realization of a topological crystalline insulator in SnTe
• Two Dimensional Ising Superconductivity in Gated MoS${}_2$
• Topological crystalline insulator states in Pb(1-x)Sn(x)Se
• Giant Anharmonic Phonon Scattering in PbTe
• Observation of topological superconductivity on the surface of an iron-based superconductor
• A topological crystalline insulator (TCI) phase via topological phase transition and crystalline mirror symmetry
• Band structure engineering in (Bi1-xSbx)2Te3 ternary topological insulators
• Chiral Majorana edge state in a quantum anomalous Hall insulator-superconductor structure
• Above 400 K Robust Perpendicular Ferromagnetic Phase in a Topological Insulator
• Quantum anomalous Hall effect driven by magnetic proximity coupling in all-telluride based heterostructure
• Two types of Dirac-cone surface states on (111) surface of topological crystalline insulator SnTe
• Critical enhancement of thermopower in a chemically tuned polar semimetal MoTe${}_2$
• Superconducting properties of the In substituted Topological Crystalline Insulator, SnTe
• A pressure-induced topological phase with large Berry curvature in Pb${}_{1-x}$Sn${}_x$Te
• Resonance-state-induced superconductivity at high Indium contents in In-doped SnTe
• Topological semimetals in the SnTe material class: Nodal lines and Weyl points
• Superconductivity induced by In substitution into the topological crystalline insulator Pb(0.5)Sn(0.5)Te
• Indium substitution effect on the topological crystalline insulator family (Pb${}_{1-x}$Sn${}_x$)${}_{1-y}$In${}_y$Te: Topological and superconducting properties
• Tailoring band-structure and band-filling in a simple cubic (IV, III) - VI superconductor

Cited by in corpus (2)

• Superconductivity in tin telluride films grown by molecular beam epitaxy
• Metallicity-driven polar transitions in topological epilayers