Competing quantum orders in 6R-TaS2 revealed by pressure
V Sazgari1, J N Graham1, S S Islam1
1PSI Center for Neutron and Muon Sciences, 5232 Villigen PSI, Switzerland.
Nature Communications
|April 30, 2026
Summary
Researchers studied 6R-TaS2, finding that superconductivity and charge density waves compete. Applying pressure suppresses the nonlinear Hall effect, revealing insights into quantum phenomena in this material.
Area of Science:
- Condensed Matter Physics
- Quantum Materials Science
Background:
- 6R-TaS2 exhibits charge density wave (CDW) order, superconductivity, and a unique temperature scale (T*) associated with nonlinear Hall effect (NHE) and magnetoresistance.
- The interplay between CDW, superconductivity, and NHE in 6R-TaS2 is not well understood.
Purpose of the Study:
- To investigate the nature of superconducting pairing and the origin of NHE in 6R-TaS2.
- To elucidate the relationship between CDW, superconductivity, and NHE under varying conditions.
Main Methods:
- Muon-spin rotation spectroscopy to probe magnetic order and superconducting properties.
- Magnetotransport measurements to study electrical transport phenomena.
- Hydrostatic pressure techniques to tune material properties.
Main Results:
- A nodal superconducting state with low superfluid density was identified at ambient pressure, with no magnetic order below T*.
- Under pressure, superfluid density and superconducting transition temperature increase, nodal superconductivity becomes nodeless, and CDW onset is suppressed.
- The NHE and magnetoresistance are highly sensitive to pressure, indicating their fragility and suppression below 0.2 GPa.
Conclusions:
- Superconductivity, charge order, and NHE in 6R-TaS2 are competing phenomena.
- Weakened interlayer coupling and shared electronic states drive these competing interactions.
- Magnetism is ruled out as the origin of the NHE.
Related Concept Videos
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.3K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
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...
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...
1.3K
03:06The Pauli Exclusion Principle
51.7K
The arrangement of electrons in the orbitals of an atom is called its electron configuration. We describe an electron configuration with a symbol that contains three pieces of information:
51.7K
03:51Molecular Orbital Theory II
21.7K
Molecular Orbital Energy Diagrams
21.7K
01:34Woodward–Hoffmann Selection Rules and Microscopic Reversibility
2.2K
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
2.2K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
47.5K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...
47.5K
01:10Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule
2.9K
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1 triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the...
2.9K