Berry curvature hot spots in two-dimensional materials with broken inversion symmetry are responsible for the existence of transverse valley currents, which give rise to giant nonlocal dc voltages. Recent experiments in high-quality gapped graphene have highlighted a saturation of the nonlocal resistance as a function of the longitudinal charge resistivity ρc,xx , when the system is driven deep into the insulating phase. The origin of this saturation is, to date, unclear. In this work we show that this behavior is fully compatible with bulk topological transport in the regime of large valley Hall angles (VHAs). We demonstrate that, for a fixed value of the valley diffusion length, the dependence of the nonlocal resistance on ρc,xx weakens for increasing VHAs, transitioning from the standard ρ3 c,xx power law to a result that is independent of ρc,xx .

Nonlocal topological valley transport at large valley Hall angles

Polini, Marco;Taddei, Fabio;Beconcini, Michael
2016

Abstract

Berry curvature hot spots in two-dimensional materials with broken inversion symmetry are responsible for the existence of transverse valley currents, which give rise to giant nonlocal dc voltages. Recent experiments in high-quality gapped graphene have highlighted a saturation of the nonlocal resistance as a function of the longitudinal charge resistivity ρc,xx , when the system is driven deep into the insulating phase. The origin of this saturation is, to date, unclear. In this work we show that this behavior is fully compatible with bulk topological transport in the regime of large valley Hall angles (VHAs). We demonstrate that, for a fixed value of the valley diffusion length, the dependence of the nonlocal resistance on ρc,xx weakens for increasing VHAs, transitioning from the standard ρ3 c,xx power law to a result that is independent of ρc,xx .
File in questo prodotto:
File Dimensione Formato  
PhysRevB.94.121408.pdf

accesso aperto

Descrizione: journal article full text
Tipologia: Altro materiale allegato
Licenza: Solo Lettura
Dimensione 238.28 kB
Formato Adobe PDF
238.28 kB Adobe PDF

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/91922
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 27
  • ???jsp.display-item.citation.isi??? 27
  • OpenAlex ND
social impact