Direct band structure measurement of a buried two-dimensional electron gas

Abstract

Buried two dimensional electron gasses (2DEGs) have recently attracted considerable attention as a testing ground for both fundamental physics and quantum computation applications. Such 2DEGs can be created by phosphorus delta (δ) doping of silicon, a technique in which a dense and narrow dopant profile is buried beneath the Si surface. Phosphorous δ-doping is a particularly attractive platform for fabricating scalable spin quantum bit architectures, compatible with current semiconductor technology. The band structure of the δ-layers that underpin these devices has been studied intensely using different theoretical methods, but it has hitherto not been possible to directly compare these predictions with experimental data. Here we report the first measurement of the electronic band structure of a δ-doped layer below the Si(001) surface by angle resolved photoemission spectroscopy (ARPES). Our measurements confirm the layer to be metallic and give direct access to the Fermi level position. Surprisingly, the direct observation of the states is possible despite them being buried far below the surface. Using this experimental approach, buried states in a wide range of other material systems, including metallic oxide interfaces, could become accessible to direct spectroscopic investigations.

References in corpus (2)

• Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3
• Quantum many-body interactions in digital oxide superlattices

Cited by in corpus (18)

• Observation of topological crystalline insulator surface states on (111)-oriented Pb${}_{1-x}$Sn${}_x$Se films
• Bulk Band Structure of Bi${}_2$Te${}_3$
• Accessing the spectral function of in operando devices by angle-resolved photoemission spectroscopy
• Roadmap on Atomic-scale Semiconductor Devices
• Observation and origin of the $\Delta$-manifold in Si:P $\delta$-layers
• One-dimensional spin texture of Bi(441); Quantum Spin Hall properties without a topological insulator
• Electronic properties of delta-doped phosphorus layers in silicon and germanium
• Simultaneous conduction and valence band quantisation in ultra-shallow, high density doping profiles in semiconductors
• Momentum-space imaging of ultra-thin electron liquids in delta-doped silicon
• Fragility of the Dirac Cone Splitting in Topological Crystalline Insulator Heterostructures
• Electronic structure of boron and aluminum $\delta$-doped layers in silicon
• Probing the Atomic Arrangement of Sub-Surface Dopants in a Silicon Quantum Device Platform
• A reduced-temperature process for preparing atomically clean Si(100) and SiGe(100) surfaces with vapor HF
• Direct measurement of 2DEG states in shallow Si:Sb $\delta$-layers
• First principles band structure of interacting phosphorus and boron/aluminum $\delta$-doped layers in silicon
• Photoemission response of 2D states
• Quantifying Atom-scale Dopant Movement and Electrical Activation in Si:P Monolayers
• Silicon Donor Array as a Disordered One-Dimensional Electron Gas