Nature of the many-body excitations in a quantum wire: theory and experiment
| Autor: | Ian Farrer, M. Moreno, Y Jin, A. S. Anirban, C. J. B. Ford, David A. Ritchie, Gac Jones, Andrew J. Schofield, WK Tan, Oleksandr Tsyplyatyev, J. Griffiths |
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| Přispěvatelé: | Ford, Christopher [0000-0002-4557-3721], Ritchie, David [0000-0002-9844-8350], Apollo - University of Cambridge Repository |
| Rok vydání: | 2015 |
| Předmět: |
Physics
Local density of states Condensed matter physics Strongly Correlated Electrons (cond-mat.str-el) 010308 nuclear & particles physics Quantum wire Order (ring theory) FOS: Physical sciences Fermion Electron 01 natural sciences 7. Clean energy Symmetry (physics) 3. Good health Condensed Matter - Strongly Correlated Electrons Luttinger liquid Quantum mechanics 0103 physical sciences cond-mat.str-el 010306 general physics Spin-½ |
| ISSN: | 2469-9950 |
| DOI: | 10.48550/arxiv.1508.07125 |
| Popis: | The natural excitations of an interacting one-dimensional system at low energy are hydrodynamic modes of Luttinger liquid, protected by the Lorentz invariance of the linear dispersion. We show that beyond low energies, where quadratic dispersion reduces the symmetry to Galilean, the main character of the many-body excitations changes into a hierarchy: calculations of dynamic correlation functions for fermions (without spin) show that the spectral weights of the excitations are proportional to powers of $\mathcal{R}^{2}/L^{2}$, where $\mathcal{R}$ is a length-scale related to interactions and $L$ is the system length. Thus only small numbers of excitations carry the principal spectral power in representative regions on the energy-momentum planes. We have analysed the spectral function in detail and have shown that the first-level (strongest) excitations form a mode with parabolic dispersion, like that of a renormalised single particle. The second-level excitations produce a singular power-law line shape to the first-level mode and multiple power-laws at the spectral edge. We have illustrated crossover to Luttinger liquid at low energy by calculating the local density of state through all energy scales: from linear to non-linear, and to above the chemical potential energies. In order to test this model, we have carried out experiments to measure momentum-resolved tunnelling of electrons (fermions with spin) from/to a wire formed within a GaAs heterostructure. We observe well-resolved spin-charge separation at low energy with appreciable interaction strength and only a parabolic dispersion of the first-level mode at higher energies. We find structure resembling the second-level excitations, which dies away rapidly at high momentum in line with the theoretical predictions here. Comment: 23 pages, 10 figures, 2 tables |
| Databáze: | OpenAIRE |
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