Collapse of minibands in far-infrared irradiated superlattices

Holthaus, Martin

doi:10.1103/physrevlett.69.351

Cited by 430 publications

(343 citation statements)

References 9 publications

Supporting

Mentioning

336

Contrasting

Unclassified

Order By: Relevance

“…In particular, the application of an appropriately controlled periodic drive to these systems brings quantum transport and diffusion to an almost complete stop [5]. In THz-driven SLs and WSLs, the latter of which are also called as dynamic WSLs (DWSLs), such spatial localization, called as dynamic localization (DL), is characterized by the collapse of quasienergy minibands [6,7]. It has been found that DL in the DWSL leads to the formation of sharp peaks in the optical spectra, and these are therefore more enhanced than or comparable to those in the corresponding WSL (without THz driving) [8,9].…”

Section: Introductionmentioning

confidence: 99%

Instability of dynamic localization in the intense terahertz-driven semiconductor Wannier-Stark ladder due to the dynamic Fano resonance

et al. 2010

View full text Add to dashboard Cite

The lifetime of an electronic Floquet state in a semiconductor Wannier-Stark ladder (WSL) driven by an intense monochromatic THz wave is examined based on the R-matrix Floquet theory, in which an excess density of state (DOS) corresponding to the lifetime is calculated. It is revealed that the dynamic localization (DL) characteristic of this system is unstable against Fano resonance (FR)-like inter-miniband decay mechanism caused by THz-mediated ac-Zener tunneling; in this study, this is termed as dynamic Fano resonance (DFR). The DFR is considered to be a new FR mechanism characterized by both tunable ac-ZT coupling and coexistence with shape resonance.The result obtained here is in sharp contrast with the conventional understanding without the introduction of DFR, in which the DL is very stable such that its lifetime is comparable to or greater than that of the associated WSL. It is found that the DFR mechanism generally becomes more dominant with an increase in the strength of the bias field. Further, we discuss the observation that the spectral pattern of the excess DOS is more involved for a single-photon resonant transition, namely, Ω = ω, than that for a two-photon resonant transition, namely, Ω = 2ω, where Ω and ω represent a Bloch frequency and a THz frequency, respectively. In addition, the criterion for the applicability of the DFR to the present system is also obtained.

show abstract

Section: Introductionmentioning

confidence: 99%

Instability of dynamic localization in the intense terahertz-driven semiconductor Wannier-Stark ladder due to the dynamic Fano resonance

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Although for usual systems, the pair tunneling is much weaker than the single particle tunneling, their ratio can be tuned experimentally with the method of shaking the optical lattice [31][32][33][34]. So the conclusion drawn here can be tested within the current experimental techniques.…”

Section: Discussionmentioning

confidence: 96%

Extended two-site Bose–Hubbard model with pair tunneling: spontaneous symmetry breaking, effective ground state and fragmentation

Zhu

Zhang

2015

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

The extended Bose-Hubbard model for a double-well potential with pair tunneling is studied through both exact diagonalization and mean field theory (MFT). When pair tunneling is strong enough, the ground state wavefunction predicted by the MFT is complex and doubly degenerate while the quantum ground state wavefunction is always real and unique. The time reversal symmetry is spontaneously broken when the system transfers from the quantum ground state into one of the mean field ground states upon a small perturbation. As the gap between the lowest two levels decreases exponentially with particle number, the required perturbation inducing the spontaneous symmetry breaking (SSB) is infinitesimal for particle number of typical cold atom systems. The quantum ground state is further analyzed with the Penrose-Onsager criterion, and is found to be a fragmented condensate. The state also develops the pair correlation and has non-vanishing pair order parameter instead of the conventional single particle order parameter. When this model is generalized to optical lattice, a pair superfluid can be generated. The mean field ground state can be regarded as effective ground state in this simple model. The detailed computation for this model enables us to offer an in-depth discussion of the relation between SSB and effective ground state, giving a glimpse on how nonlinearity arises in the SSB of a quantum system.

show abstract

“…To obtain the current expectation value, we solve equation (11) and insert the solution into equation (12) which yields…”

Section: Counting Statisticsmentioning

confidence: 99%

“…A possible way to achieve this is driving the conductor by an electric dipole field. Then for not too small frequencies, the driving essentially renormalizes the inter-dot tunnel coupling [9][10][11][12] and, thus, allows the emulation of a dimer chain with highly tunable tunneling. In the corresponding transport setting, i.e., in the presence of electron source and drain, one expects a corresponding current suppression [13,14] which has been measured in double quantum dots [15,16].…”

Section: Introductionmentioning

confidence: 99%

Transport, shot noise, and topology in AC-driven dimer arrays

Niklas¹,

Benito²,

Kohler³

et al. 2016

Nanotechnology

View full text Add to dashboard Cite

We analyze an AC-driven dimer chain connected to a strongly biased electron source and drain. It turns out that the resulting transport exhibits fingerprints of topology. They are particularly visible in the driving-induced current suppression and the Fano factor. Thus, shot noise measurements provide a topological phase diagram as a function of the driving parameters. The observed phenomena can be explained physically by a mapping to an effective time-independent Hamiltonian and the emergence of edge states. Moreover, by considering quantum dissipation, we determine the requirements for the coherence properties in a possible experimental realization. For the computation of the zero-frequency noise, we develop an efficient method based on matrix-continued fractions.

show abstract

Collapse of minibands in far-infrared irradiated superlattices

Cited by 430 publications

References 9 publications

Instability of dynamic localization in the intense terahertz-driven semiconductor Wannier-Stark ladder due to the dynamic Fano resonance

Instability of dynamic localization in the intense terahertz-driven semiconductor Wannier-Stark ladder due to the dynamic Fano resonance

Extended two-site Bose–Hubbard model with pair tunneling: spontaneous symmetry breaking, effective ground state and fragmentation

Transport, shot noise, and topology in AC-driven dimer arrays

Contact Info

Product

Resources

About