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Quantum Phase Transition at Nonzero Doping in a Random t-J Model
Henry Shackleton1, Alexander Wietek2, Antoine Georges2,3,4,5
1Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Physical Review Letters
|April 16, 2021
Summary
This study reveals a metallic spin glass phase in a random t-J model, extending from insulating states up to a critical doping level. This metallic phase exhibits unique electronic properties and connections to quantum chaos models.
Area of Science:
- Condensed Matter Physics
- Quantum Materials Science
Background:
- The t-J model describes strongly correlated electrons in materials like cuprates.
- Understanding the interplay of correlations, disorder, and magnetism is crucial for novel electronic phases.
Purpose of the Study:
- To investigate the properties of a t-J model with random all-to-all interactions.
- To explore the emergence and characteristics of metallic spin glass phases.
- To connect these findings to quantum chaos and disordered Fermi surfaces.
Main Methods:
- Exact diagonalization on finite clusters.
- Analysis of dynamic spin susceptibility.
- Examination of thermodynamic and entanglement entropy.
- Study of electron energy distribution functions.
Main Results:
- A metallic spin glass phase exists up to a critical doping p ≈ 1/3.
- Signatures of Sachdev-Ye-Kitaev models observed in dynamic spin susceptibility near p_c.
- Maxima in entropy, entanglement entropy, and compressibility indicate a phase transition.
- Disordered Luttinger-volume Fermi surface observed for p > p_c, breaking down for p < p_c.
Conclusions:
- Random all-to-all interactions in the t-J model capture essential physics of correlated electron systems.
- The metallic spin glass phase represents a novel state of matter with unique electronic properties.
- The study provides insights into the breakdown of Fermi surface properties in strongly correlated disordered systems.
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