The topological inequivalence of Hall bar versus Corbino geometries in real space

TL;DR

This paper investigates how topology influences electron behavior in Hall bar and Corbino geometries, revealing that their topological differences affect local electronic properties and quantization, with implications for experimental distinction.

Contribution

It demonstrates that the bulk regions are not incompressible during the quantized Hall plateau and proposes experiments to distinguish topological effects in different geometries.

Findings

Bulk regions are not incompressible during the plateau

Quantization remains unaffected by genus changes in the Hall bar

Proposes experiments to differentiate topological properties

Abstract

This work discusses the effect of topology in the frame of direct Coulomb interactions, considering two distinct geometries, namely the Hall bar and the Corbino disc. In the mainstream approaches to the quantized Hall effect, the consequences of interactions are usually underestimated. Here, we investigate the electron number density, potential and current distributions within the screening theory that considers electron-electron interactions. Inclusion of direct Coulomb interaction and realistic boundary conditions result in local metal-like compressible and (Topological) insulator-like incompressible regions. Consequently, we show that the bulk of both geometries in coordinate space is not incompressible throughout the quantized Hall plateau. Furthermore, placing two inner contacts within the Hall bar geometry shows that the quantization is unaffected by changing the genus number in real space. Finally, we propose novel experiments which will enable us to distinguish the topological properties of the two geometries in the configuration space.