Manipulating Giant Rashba Valley Splitting and Quantum Hall States in Few-Layer Black Arsenic by Electrostatic Gating

Abstract

Exciting phenomena may emerge in non-centrosymmetric two-dimensional (2D) electronic systems when spin-orbit coupling (SOC) interplays dynamically with Coulomb interactions, band topology, and external modulating forces, etc. Here, we report illuminating synergetic effects between SOC and Stark in centrosymmetric few-layer black arsenic (BAs), manifested as giant Rashba valley splitting and exotic quantum Hall states (QHS) reversibly controlled by electrostatic gating. The unusual finding is rooted in the puckering square lattice of BAs, in which heavy $4p$ orbitals form highly asymmetric $\Gamma$ valley with the $p_z$ symmetry and $D$ valleys of the $p_x$ origin, located at the Brillouin zone (BZ) center and near the time reversal invariant momenta of $X$, respectively. When the structure inversion symmetry is broken by perpendicular electric field, giant Rashba SOC is activated for the $p_x$ bands to produce strong spin-polarized $D^{+}$ and $D^{-}$ valleys related by time-reversal symmetry, coexisting with weak $\Gamma$ Rashba bands constrained by the $p_z$ symmetry. Intriguingly, strong Stark effect shows the same $p_x$-orbital selectiveness for $D$, collectively shifting the valence band maximum of $D^{\pm }$ valleys to exceed the $\Gamma$ pockets. Such an orchestrating effect between SOC and Stark allows us to realize gate-tunable spin valley manipulations for 2D hole gas, as revealed by unconventional magnetic field triggered even-to-odd transitions in QHS. For electron doping, the quantization of the $\Gamma$ Rashba bands is characterized by peculiar density-dependent transitions in band topology from two parabolic valleys to a unique inner-outer helical structure when charge carrier concentrations increase.

arXiv comment9 pages, 4 figures

References in corpus (21)

• Two-Dimensional Gas of Massless Dirac Fermions in Graphene
• Topological Insulators
• Experimental Observation of Quantum Hall Effect and Berry's Phase in Graphene
• Black phosphorus field-effect transistors
• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• New Perspectives for Rashba Spin-Orbit Coupling
• Observation of tunable bandgap and anisotropic Dirac semimetal state in black phosphorus
• Observation of topological surface state quantum Hall effect in an intrinsic three-dimensional topological insulator
• Quantum Hall Effect in Black Phosphorus Two-dimensional Electron Gas
• Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride
• Quantum Hall Effect in Ultrahigh Mobility Two-dimensional Hole Gas of Black Phosphorus
• Unconventional Quantum Hall Effect and Tunable Spin Hall Effect in MoS2 Trilayers
• Defects controlled hole doping and multi-valley transport in SnSe single crystals
• Interactions and magnetotransport through spin-valley coupled Landau levels in monolayer MoS${}_2$
• Density-Dependent Quantum Hall States and Zeeman Splitting in Monolayer and Bilayer WSe${}_2$
• Conductance through a helical state in an InSb nanowire
• Rashba-like spin splitting along three momentum directions in trigonal layered PtBi2
• Quantum Hall Effect in Electron-Doped Black Phosphorus Field-Effect Transistors
• Odd-integer quantum Hall states and giant spin susceptibility in p-type few-layer WSe2
• Hierarchical spin-orbital polarisation of a giant Rashba system
• Black Arsenic: A Layered Semiconductor with Extreme in-plane Anisotropy

Cited by in corpus (8)

• Nanomaterials for Quantum Information Science and Engineering
• Discovery of a hybrid topological quantum state in an elemental solid
• Even-integer Quantum Hall Effect in an Oxide Caused by Hidden Rashba Effect
• Electronic Self-passivation of Single Vacancy in Black Phosphorus via a Controlled Ionization
• Giant anisotropic band flattening in twisted $\Gamma$ valley semiconductor bilayers
• Emergence of Rashba spin valley state in two-dimensional strained bismuth oxychalcogenides Bi${}_2$O${}_2$Se
• Atomically thin obstructed atomic insulators with robust edge modes and quantized spin Hall effect
• Electrically switchable non-relativistic Zeeman spin splittings in collinear antiferromagnets