# Competing Electronic Phases near the Onset of Superconductivity in Hole-doped SrFe2As2

## TL;DR

This study reveals a complex phase diagram in Na-doped SrFe2As2, identifying nine electronic phases near the transition from antiferromagnetism to superconductivity, including a new magnetic phase that strongly competes with superconductivity.

## Contribution

The paper uncovers a new magnetic phase in Na-doped SrFe2As2 and proposes it as a double-Q phase with unique magnetic properties, advancing understanding of competing electronic orders.

## Key findings

- Identification of nine distinct electronic phases.
- Discovery of a new magnetic phase competing with superconductivity.
- Proposal of a double-Q magnetic order with temperature-dependent reorientation.

## Abstract

An intriguingly complex phase diagram of Na-doped SrFe2As2 is uncovered using high-resolution thermal-expansion, magnetization and heat-capacity measurements. The detailed temperature dependence of the orthorhombic distortion and the anisotropy of the uniform magnetic susceptibility provide evidence for nine distinct electronic phases near the transition region between stripe antiferromagnetism and unconventional superconductivity. In particular, we report the finding of a new magnetic phase which competes surprisingly strongly with superconductivity. From theoretical studies we propose that this phase is a double-Q phase consisting of a mixture of symmetry-distinct commensurate magnetic orders with a peculiar temperature-dependent magnetic moment reorientation.