Reentrant Localization Transition in a Quasiperiodic Chain

Abstract

Broken inversion symmetry in atomic structure can lead to the emergence of specific functionalities at the nanoscale. Therefore, realizing 2D materials in Janus form is a growing field, which offers unique features and opportunities. In this paper, we investigate the structural, vibrational, elastic, piezoelectric, and electronic properties of Janus BiXY (X = S, Se, Te and Y = F, Cl, Br, I) monolayers based on first-principle methods. The structural optimization and vibrational frequency analysis reveal that all of the proposed structures are dynamically stable. Additionally, ab initio molecular dynamics simulations verify the thermal stability of these structures even at elevated temperatures. The mechanical response of the Janus BiXY crystals in the elastic regime is investigated in terms of in-plane stiffness and the Poisson ratio, and the obtained results ascertain their mechanical flexibility. The piezoelectric stress and strain coefficient analysis demonstrates the appearance of strong out-of-plane piezoelectricity, which is comparable with the Janus transition metal dichalcogenide monolayers. The calculated electronic band structures reveal that except for BiTeF, all Janus BiXY monolayers are indirect band gap semiconductors, and their energy band gaps span from the infrared to the visible part of the optical spectrum. Subsequently, large Rashba spin splitting is observed in electronic band structures when the spin-orbit coupling is included. The obtained results point out Janus 2D BiXY structures as promising materials for a wide range of applications in nanoscale piezoelectric and spintronics fields.

Non-Hermiticity-induced reentrant localization in a quasiperiodic lattice

“…interesting phenomenon termed relocalization or re-delocalization transition has been revealed in generalized AAH model [60][61][62]. In this paper, we demonstrate that the non-Hermiticity can induce a reentrant localization.…”

“…We emphasize that the reentrant localization is not exclusive to the non-Hermitian dimerized lattice. In fact, Hermitian system may exhibit similar behavior under some fine-tuned parameter settings [62]. The asymmetric hopping can, however, largely extend the parameters regime where the reentrant localization occurs, and therefore offers an additional experiment knob detecting richer physics.…”

Non-Hermitian gap closure and delocalization in interacting directed polymers

“…The non-monotonic dependence of the critical force angle on disorder strength is consistent with a switch in the dominant localization mechanism, from band-insulator physics at low disorder to Anderson localization of single-particle eigenstates at high disorder. This mechanism could serve as a non-Hermitian version of a reentrant localization transition, reminiscent of similar phenomena in Hermitian systems [63,64].…”

Topological Anderson insulators with different bulk states in quasiperiodic chains

“…* danweizhang@m.scnu.edu.cn Quasiperiodic systems with incommensurate modulations in the potential or hopping terms are an ideal platform to study the Anderson localization and topological phases of matter . The quasiperiodic disorder can lead to localization phenomena without counterparts of random disorder in low dimensions, such as the localization transition [47][48][49][50], the intermediate phase consisting of both localized and extended states [51,[69][70][71][72][73][74], and the critical phase consisting of only critically localized states [67,[75][76][77][78][79]. Meanwhile, the topological charge pumping [49] can be realized in the paradigmatic 1D Aubry-André-Harper model [47,48] and its variety of generalizations [53][54][55][56][57][58][59][60].…”