Uniaxial-Strain Tuning of the Intertwined Orders in BaFe$_2$(As$_{1-x}$P$_{x}$)$_2$

TL;DR

This study demonstrates that uniaxial strain can effectively tune electronic phases such as nematicity, antiferromagnetism, and superconductivity in BaFe$_2$(As$_{1-x}$P$_{x}$)$_2$, providing a disorder-free alternative to chemical doping for exploring intertwined orders.

Contribution

The paper introduces uniaxial strain as a novel method to control electronic phases in iron-based superconductors, avoiding lattice disorder caused by chemical substitution.

Findings

Uniaxial strain significantly alters antiferromagnetic order and superconductivity.

Strain-tuned phase diagrams differ from chemically doped ones.

Strain application reveals the interplay of electronic nematicity, magnetism, and superconductivity.

Abstract

An experimental determination of electronic phase diagrams of high-transition temperature (high-$T_c$) superconductors forms the basis for a microscopic understanding of unconventional superconductivity. For most high-$T_c$ superconductors, the electronic phase diagrams are established through partial chemical substitution, which also induces lattice disorder. Here we show that symmetry-specific uniaxial strain can be used to study electronic phases in iron-based superconductors, composed of two-dimensional nearly square iron lattice planed separated by other elements. By applying tunable uniaxial strain along different high symmetry directions and carrying out transport measurements, we establish strain-tuning dependent electronic nematicity, antiferromagnetic (AF) order, and superconductivity of BaFe$_2$(As$_{1-x}$P$_{x}$)$_2$ superconductor. We find that uniaxial strain along the nearest Fe-Fe direction can dramatically tune the AF order and superconductivity, producing an electronic phase diagram clearly different from the chemical substitution-induced one. Our results thus establish strain tuning as a way to study the intertwined orders in correlated electron materials without using chemical substitution.