Related Experiment Video
Updated: May 20, 2025

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
Signature of Preformed Pairs in Angle-Resolved Photoemission Spectroscopy
Klemen Kovač1,2, Alberto Nocera3,4, Andrea Damascelli3,4
1J. Stefan Institute, 1000 Ljubljana, Slovenia.
Abstract:
We use density matrix renormalization group (DMRG) and variational exact diagonalization (VED) to calculate the single-electron removal spectral weight for the Hubbard-Holstein model at low electron densities. Tuning the strength of the electron-phonon coupling and of the Hubbard repulsion allows us to contrast the results for a liquid of polarons versus a liquid of bipolarons. The former shows spectral weight up to the Fermi energy, as expected for a metal. The latter has a gap in its spectral weight, set by the bipolaron binding energy, although this is also a (strongly correlated) metal. This difference suggests that angle-resolved photoemission spectroscopy could be used to identify liquids of pre-formed pairs. Furthermore, we show that the one-dimensional liquid of incoherent bipolarons is well approximated by a "Bose sea" of bosons that are hard-core in momentum space, occupying the momenta inside the Fermi sea but otherwise noninteracting. This new proposal for a strongly correlated many-body wave function opens the way for studying various other properties of incoherent (nonsuperconducting) liquids of preformed pairs in any dimension.
Related Concept Videos
Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Double Resonance Techniques: Overview
Spin decoupling is usually achieved by...
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
Atomic Spectroscopy: Absorption, Emission, and Fluorescence

