Band Structures of Ultrathin Bi(110) Films on Black Phosphorus Substrates Using Angle-Resolved Photoemission Spectroscopy

Abstract

The band structures of two-monolayer Bi(110) films on black phosphorus substrates are studied using angleresolved photoemission spectroscopy. Within the band gap of bulk black phosphorus, the electronic states near the Fermi level are dominated by the Bi(110) film. The band dispersions revealed by our data suggest that the orientation of the Bi(110) film is aligned with the black phosphorus substrate. The electronic structures of the Bi(110) film strongly deviate from the band calculations of the free-standing Bi(110) film, suggesting that the substrate can significantly affect the electronic states in the Bi(110) film. Our data show that there are no non-trivial electronic states in Bi(110) films grown on black phosphorus substrates.

Enhanced Berry Curvature Dipole and Persistent Spin Texture in the Bi(110) Monolayer

“…The Bi(110) monolayer crystallizes with a distorted phosphorene structure that belongs to the nonsymmorphic space group Pmn 2 1 , − containing several symmetry operations of glide planes and screw axes (see Table ). The optimized lattice constants are a = 4.90 Å and b = 4.59 Å, which agree well with the experimental − and theoretical ,, results reported. A notable structural feature is the finite out-of-plane buckling (Figure a), resulting from the vertical shift of the two centered Bi atoms.…”

Atomically Thin Quantum Spin Hall Insulators

“…[123] The electronic structure of bismuth (Z = 83) surfaces have been extensively investigated, both theoretically [84,86,87,89,97,103,125,130,134,135] and experimentally. [59,[126][127][128][129][136][137][138][139][140][141][142][143][144][145][146][147] Recently, bismuth has been shown to be a higher order topological insulator (HOTI), [129] possessing helical "hinge" states that consist of 1D gapless Kramers pairs, like the QSH edge, around specific facets of the crystal, which exists even for 3D bulk samples. As a consequence, both monolayers of Bi(111) (buckled honeycomb structure, Figure 4B) and Bi(110) (puckered honeycomb structure, Figure 4C), have been predicted to host gapless edge modes, consistent with those in a quantum spin Hall insulator, tunable by strain and electric field.…”

Achieving a Large Energy Gap in Bi(110) Atomically Thin Films

“…[1][2][3][4][5] Being a heavy element with unique and anomalous electronic properties, the semimetal bismuth (Bi) is one of the most extensively studied materials and has played an exceptional role in revealing many interesting phenomena in solid-state physics. [6][7][8][9][10][11][12] In particular, ultrathin Bi films have provided a representative platform for fundamental and technological explorations through delicate tailoring of their atomic and electronic structures, [13][14][15][16][17][18][19][20][21] interfacial structure, [2,3,[22][23][24][25] charge doping, [21,26] etc. When Bi is deposited on alternative substrates with a few-layer atomic thickness, such as Si(111), [27] highly oriented pyrolytic graphite (HOPG), [13,22,28] epitaxial graphene, [23,29] NbSe 2 , [21,26] and ferromagnetic Fe 3 GeTe 2 , [25] Bi normally forms Bi(110)-oriented thin films.…”

“…Atomic buckling has been predicted to be important for modulating the electronic properties of ultrathin Bi(110) layers. [13][14][15][16] Despite extensive studies on Bi(110) films grown on various Metal-insulator transition has long been one of the key subjects in condensed matter systems. Herein, the emergence of a large energy gap (E g , 0.8-1.0 eV) in Bi(110) two-atomic-layer nanoribbons grown on a SnSe(001) substrate is reported, which normally has an intrinsic semimetal-like characteristic.…”

“…Atomic buckling has been predicted to be important for modulating the electronic properties of ultrathin Bi(110) layers. [ 13–16 ] Despite extensive studies on Bi(110) films grown on various substrates, [ 13,21,23,25–29 ] experimental proof of the creation of DBP Bi(110) with atomically resolved Δ h and exploration of its associated electronic structures have been limited. In our study, we introduced substrates with a DBP structure, [ 30–35 ] such as SnSe(001), aiming to induce atomic buckling in Bi(110) to modulate its electronic properties.…”