Quantum transport in quasiperiodic lattice systems in the presence of Büttiker probes

Saha, Madhumita; Venkatesh, B. Prasanna; Agarwalla, Bijay Kumar

doi:10.1103/physrevb.105.224204

Cited by 14 publications

(2 citation statements)

References 64 publications

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“…For | F | > 2, i.e, Fermi energy outside the system band, transport becomes diffusive even at very small values of τ p . The cases away from band-edges have been investigated in several previous works [20,36,45].…”

Section: Sb (Nmentioning

confidence: 99%

Environment assisted superballistic scaling of conductance

Saha¹,

Agarwalla²,

Kulkarni³

et al. 2022

Preprint

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We find that, in the presence of weak incoherent effects from surrounding environments, the zero temperature conductance of nearest neighbour tight-binding chains exhibits a counter-intuitive power-law growth with system length at band-edges, indicating superballistic scaling. This fascinating environment assisted superballistic scaling of conductance occurs over a finite but extended regime of system lengths. This scaling regime can be systematically expanded by decreasing the coupling to the surrounding environments. There is no corresponding analog of this behavior for isolated systems. This superballistic scaling stems from an intricate interplay of incoherent effects from surrounding environments and exceptional points of the system's transfer matrix that occur at every band-edge.

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Section: Sb (Nmentioning

confidence: 99%

Environment assisted superballistic scaling of conductance

Saha¹,

Agarwalla²,

Kulkarni³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…This involves tracing out the degrees of freedom of the environment under certain well-known approximations, resulting in an effective prescription for the dynamics of the reduced density matrix of the system [1,2]. In the Lindblad framework (and more generally in open quantum systems), the impact of the environment often is of two types: (i) dissipator-like [18][19][20][21][22][23][24][25][26][27] and (ii) dephasing-like [28][29][30][31][32][33][34][35][36]. The former encodes potential exchange of particles between the system and the environment whereas the latter encodes energy/heat exchange but conserving the total number of particles in the system.…”

Section: Introductionmentioning

confidence: 99%

Impact of dephasing probes on incommensurate lattices

Ghosh,

Mohanta,

Kulkarni

et al. 2024

J. Stat. Mech.

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We investigate open quantum dynamics for a one-dimensional incommensurate Aubry–André–Harper lattice chain, a part of which is initially filled with electrons and is further connected to dephasing probes at the filled lattice sites. This setup is akin to a step-initial configuration where the non-zero part of the step is subjected to dephasing. We investigate the quantum dynamics of local electron density, the scaling of the density front as a function of time both inside and outside of the initial step, and the growth of the total number of electrons outside the step. We analyze these quantities in all three regimes, namely, the de-localized, critical, and localized phases of the underlying lattice. Outside the initial step, we observe that the density front spreads according to the underlying nature of single-particle states of the lattice, for both the de-localized and critical phases. For the localized phase, the spread of the density front hints at a logarithmic behavior in time that has no parallel in the isolated case (i.e. in the absence of probes). Inside the initial step, due to the presence of the probes, the density front spreads in a diffusive manner for all the phases. This combination of rich and different dynamical behavior, outside and inside the initial step, results in the emergence of mixed dynamical phases. While the total occupation of electrons remains conserved, the value outside or inside the initial step turns out to have a rich dynamical behavior. Our work is widely adaptable and has interesting consequences when disordered/quasi-disordered systems are subjected to a thermodynamically large number of probes.

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Long-range charge transport in homogeneous and alternating-rigidity chains

Liang

Segal

2022

The Journal of Chemical Physics

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We study the interplay of intrinsic-electronic and environmental factors in long-range charge transport across molecular chains with up to N ∼ 80 monomers. We describe the molecular electronic structure of the chain with a tight-binding Hamiltonian. Thermal effects in the form of electron decoherence and inelastic scattering are incorporated with the Landauer–Büttiker probe method. In short chains of up to ten units, we observe the crossover between coherent (tunneling, ballistic) motion and thermally-assisted conduction, with thermal effects enhancing the current beyond the quantum coherent limit. We further show that unconventional (nonmonotonic with size) transport behavior emerges when monomer-to-monomer electronic coupling is made large. In long chains, we identify a different behavior, with thermal effects suppressing the conductance below the coherent-ballistic limit. With the goal to identify a minimal model for molecular chains displaying unconventional and effective long-range transport, we simulate a modular polymer with alternating regions of high and low rigidity. Simulations show that, surprisingly, while charge correlations are significantly affected by structuring environmental conditions, reflecting charge delocalization, the electrical resistance displays an averaging effect, and it is not sensitive to this patterning. We conclude by arguing that efficient long-range charge transport requires engineering both internal electronic parameters and environmental conditions.

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Quantum transport in quasiperiodic lattice systems in the presence of Büttiker probes

Cited by 14 publications

References 64 publications

Environment assisted superballistic scaling of conductance

Environment assisted superballistic scaling of conductance

Impact of dephasing probes on incommensurate lattices

Long-range charge transport in homogeneous and alternating-rigidity chains

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