Two-dimensional quantum transport of multivalley (111) surface state in topological crystalline insulator SnTe thin films

Abstract

JapanSnTe (111) films, topological crystalline insulators, weak antilocalization, phase coherence length, Dirac valleysMagneto-transport properties of (111)-oriented single-crystal thin films of SnTe were investigated. SnTe (111) thin films were epitaxially grown on a BaF 2 substrate by molecular beam epitaxy. By optimizing the growth conditions and the thickness of the films, the bulk carrier density could be reduced, making it possible to detect the surface transport. In the magneto-conductance (MC) measurement, a cusp-like feature around zero magnetic field was observed, which is attributed to the weak-antilocalization effect of the transport in the Corresponding Author

Giant Linear Magnetoresistance and Carrier Density Tunable Transport in Topological Crystalline Insulator SnTe Thin Film

“…It is well known that the magneto‐conductance (MC) under a perpendicular field reflects the 2D WAL and 3D WAL, but when the film is parallel to the magnetic field, only the 3D WAL signal is exhibited. Therefore, the MC arising from the 2D WAL can be obtained from the difference between the MC under magnetic field perpendicular (Δ G ⊥ ( B )) and parallel (Δ G // ( B )) to the plane of thin film, where the 2D Δ G ( B ) = G ( B ) –G (0) = 1/ σ xx ( B ) – 1/ σ xx (0) . According to the quantum correction of the 2D diffusive transport, the WAL induced sharp cusp in Figure (e) can be fitted by using Hikami–Larkin–Nagaoka (HLN) equation where e is the charge of an electron, ħ is Planck constant, Ψ( x ) is digamma function, L Φ is the phase coherent length, and 2α represents the number of coherent transport channels .…”

“…Due to the topological origin and Dirac fermions nature of the TSSs, SnTe is expected to have excellent performance in surface/interface state carrier transport. Various quantum transport phenomena associated with the TSSs have been revealed such as weak antilocalization (WAL), two‐dimensional (2D) SdH oscillation, Aharonov–Bohm (AB) effect, and high field linear magnetoresistance (LMR) . Because of the formation of Sn vacancy site or Te antisite, SnTe always exhibits heavy p‐type conduction that increases the bulk contribution and suppresses the TSSs signal in transport .…”

Proximity-Induced Superconductivity and Quantum Interference in Topological Crystalline Insulator SnTe Thin-Film Devices

“…The theoretical prediction for the latter is supposed to yield α0 = -0.5 for one TSS contributing to transport [20]. As shown in Fig 3( other groups [24,26,27] and was attributed to the high bulk carrier concentration. Since WAL, however, is predominantly a 2D phenomenon, the bulk bands are unlikely to be the origin of the WAL [21,24,28].…”

Observation of the inverse spin Hall effect in the topological crystalline insulator SnTe using spin pumping

“…Thus, the influence of the breaking of TRS by magnetic perturbation is different in TCIs from that in other TIs. SnTe is a typical and promising TCI, in which the presence of the SSs has been experimentally confirmed by studies of angle-resolved photoemission spectroscopy, scanning tunnel spectroscopy, and electrical transports [15][16][17][18][19][20][21][22][23][24][25]. The strong spin-orbit coupling in bulk SnTe is also attractive for spintronic applications.…”