Related Experiment Videos
Delocalized fermions in underdoped cuprate superconductors
Mike Sutherland1, S Y Li, D G Hawthorn
1Department of Physics, University of Toronto, Toronto, Ontario, Canada.
Physical Review Letters
|May 21, 2005
Summary
The ground state of underdoped cuprates is a thermal metal, not an insulator. Delocalized fermionic excitations were observed in YBa2Cu3O6.33, indicating a nodal low-energy spectrum.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Superconductivity
Background:
- Underdoped cuprates exhibit complex electronic phases near the superconducting phase boundary.
- Understanding the ground state of these materials is crucial for advancing high-temperature superconductivity.
- Previous studies on La2-xSrxCuO4 suggested an insulating ground state due to competing orders.
Purpose of the Study:
- To investigate the ground state of lightly doped cuprates, specifically YBa2Cu3O6.33.
- To determine the nature of the electronic excitations in the non-superconducting state of underdoped cuprates.
- To compare the ground state properties of YBa2Cu3O6.33 with other cuprates like La2-xSrxCuO4.
Main Methods:
- Low-temperature heat transport measurements.
- Investigation of high-purity single crystals of YBa2Cu3O6.33.
- Measurements across the superconducting phase boundary at varying doping concentrations.
Main Results:
- Observation of delocalized fermionic excitations at zero energy in the non-superconducting state of YBa2Cu3O6.33.
- The ground state of underdoped cuprates was identified as a thermal metal.
- The low-energy spectrum of the thermal metal state was found to be nodal, similar to d-wave superconductors.
Conclusions:
- The ground state of underdoped cuprates is a thermal metal, characterized by delocalized fermionic excitations.
- The observed nodal spectrum in the thermal metal state provides insights into the electronic behavior of these materials.
- The contrasting insulating ground state in La2-xSrxCuO4 is attributed to competing spin-density-wave order.