Half-integer anomalous currents in 2D materials from a QFT viewpoint

Author(s)

Dudal, David ; Matusalem, Filipe ; Mizher, Ana Julia ; Rocha, Alexandre Reily ; Villavicencio, Cristian

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 12, n. 1, p. 10-pg., 2022-03-31.

Abstract

Charge carriers in Dirac/Weyl semi-metals exhibit a relativistic-like behavior. In this work we propose a novel type of intrinsic half-integer Quantum Hall effect in 2D materials, thereby also offering a topological protection mechanism for the current. Its existence is rooted in the 2D parity anomaly, without any need for a perpendicular magnetic field. We conjecture that it may occur in disturbed honeycomb lattices where both spin degeneracy and time reversal symmetry are broken. These configurations harbor two distinct gap-opening mechanisms that, when occurring simultaneously, drive slightly different gaps in each valley, causing a net anomalous conductivity when the chemical potential is tuned to be between the distinct gaps. Some examples of promising material setups that fulfill the prerequisites of our proposal are also listed to motivate looking for the effect at the numerical and experimental level. (AU)

• FAPESP's process: 17/02317-2 - Interfaces in materials: electronic, magnetic, structural and transport properties
• Grantee: Adalberto Fazzio
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 20/06896-0 - Atomistic modeling of the condensed phases of water
• Grantee: Filipe Matusalém de Souza
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/01343-7 - ICTP South American Institute for Fundamental Research: a regional center for theoretical physics
• Grantee: Nathan Jacob Berkovits
• Support Opportunities: Special Projects
• FAPESP's process: 16/12705-7 - Magnetic fields in heavy ion collisions: effects on obserbables
• Grantee: Ana Júlia Silveira Mizher
• Support Opportunities: Scholarships in Brazil - Post-Doctoral