Inducing topological transitions by a time-periodic perturbation offers a route to controlling the properties of materials. Here, we show that the adiabatic preparation of a nontrivial state involves a selective population of edge states, due to exponentially small gaps preventing adiabaticity. We illustrate this by studying graphenelike ribbons with hopping's phases of slowly increasing amplitude, as, e.g., for a circularly polarized laser slowly turned on. The induced currents have large periodic oscillations, but flow solely at the edges upon time averaging, and can be controlled by focusing the laser on either edge. The bulk undergoes a nonequilibrium topological transition, as signaled by a local Hall conductivity, the Chern marker introduced by Bianco and Resta in equilibrium. The breakdown of this adiabatic picture in the presence of intraband resonances is discussed.

Quantum annealing and nonequilibrium dynamics of Floquet Chern insulators / Privitera, Lorenzo; Santoro, Giuseppe E.. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 93:24(2016), pp. 1-5. [10.1103/PhysRevB.93.241406]

Quantum annealing and nonequilibrium dynamics of Floquet Chern insulators

Privitera, Lorenzo;Santoro, Giuseppe E.
2016

Abstract

Inducing topological transitions by a time-periodic perturbation offers a route to controlling the properties of materials. Here, we show that the adiabatic preparation of a nontrivial state involves a selective population of edge states, due to exponentially small gaps preventing adiabaticity. We illustrate this by studying graphenelike ribbons with hopping's phases of slowly increasing amplitude, as, e.g., for a circularly polarized laser slowly turned on. The induced currents have large periodic oscillations, but flow solely at the edges upon time averaging, and can be controlled by focusing the laser on either edge. The bulk undergoes a nonequilibrium topological transition, as signaled by a local Hall conductivity, the Chern marker introduced by Bianco and Resta in equilibrium. The breakdown of this adiabatic picture in the presence of intraband resonances is discussed.
93
24
1
5
241406
http://harvest.aps.org/bagit/articles/10.1103/PhysRevB.93.241406/apsxml
https://arxiv.org/abs/1508.01883
Privitera, Lorenzo; Santoro, Giuseppe E.
File in questo prodotto:
File Dimensione Formato  
Privitera_PRBRC16.pdf

non disponibili

Tipologia: Versione Editoriale (PDF)
Licenza: Non specificato
Dimensione 1.5 MB
Formato Adobe PDF
1.5 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

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: http://hdl.handle.net/20.500.11767/87949
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 26
  • ???jsp.display-item.citation.isi??? 26
social impact