Elastoresistivity in the incommensurate charge density wave phase of BaNi2(As1−xPx)2

Abstract

Electronic nematicity, the breaking of the crystal lattice rotational symmetry by the electronic fluid, is a fascinating quantum state of matter. In this work, using electronic transport under strain we investigate the electronic nematicity of BaNi2(As1−xPx)2, a candidate system for charge-induced nematicity. We report a large B1g elastoresistance coefficient that is maximized at the tetragonal-to-orthorhombic transition temperature, that slightly precedes the first-order triclinic transition. An hysteretic behavior is observed in the resistance versus strain sweeps and interpreted as the pinning of orthorhombic domains. Remarkably, the elastoresistance only onsets together with a strong enhancement of the incommensurate charge density wave of the material, strongly suggesting that this electronic instability is uniaxial in nature and drive the orthorhombic transition. The absence of sizeable elastoresistance above this electronic phase clearly contrasts dynamic and static electronic nematicity. Finally, the elastoresistance temperature dependence that strongly differs from the Curie-Weiss form of iron-based superconductors reveals major differences for the respective coupling of electronic nematicity to the lattice. Our results uncover an extremely strain-sensitive platform to study electronic anisotropy induced by a charge-density-wave instability.

Endotaxial Stabilization of 2D Charge Density Waves with Long-range Order

“…The IC phase is ordered, but the CDW can be continuously melted into a disordered hexatic-IC phase (as described in figure 3). The boundaries of the CDW phase diagram are drawn with consistency to hexatic melting of 2D collidal particles under temperature and disorder [41] as well as nematic CDWs [18,19,42].…”

Charge density waves tuned by biaxial tensile stress

“…Recently, the application of direct mechanical deformation using piezoelectric actuators 4 was successfully applied in quantum materials to drive electronic transitions. Elastoresistivity measurements performed under uniaxial stress was used to study nematic susceptibility in iron pnictides 5 – 8 or heavy fermion materials 9 . Although compatible with cryogenic temperatures, devices applying uniaxial stress have an intrinsic limitation in terms of flexibility, as only one direction of strain is controlled in the sample.…”

Superconducting state in Ba1−x Sr x Ni2As2 near the quantum critical point

“…The phenomenon of superconductivity is often accompanied by other novel charge orders, such as charge density waves (CDWs), spin density waves (SDWs) and nematic phases. [1][2][3] BaNi 2 As 2 does not exhibit magnetic order [4] but possesses rich charge orders, [5][6][7] making it an excellent platform for studying the interaction between charge orders and superconductivity. Although BaNi 2 As 2 has a structure similar to that of the 122-type iron-based superconductor BaFe 2 As 2 , [8][9][10] and an electronic phase diagram showing doping-induced T c variation, [5][6][7]11,12] there are significant differences between them in band structures and correlation effects.…”

“…[1][2][3] BaNi 2 As 2 does not exhibit magnetic order [4] but possesses rich charge orders, [5][6][7] making it an excellent platform for studying the interaction between charge orders and superconductivity. Although BaNi 2 As 2 has a structure similar to that of the 122-type iron-based superconductor BaFe 2 As 2 , [8][9][10] and an electronic phase diagram showing doping-induced T c variation, [5][6][7]11,12] there are significant differences between them in band structures and correlation effects. [13] Compared with the unconventional superconducting behavior of iron-based superconductors, BaNi 2 As 2 is a weakly coupled conventional s-wave superconductor with a very low T c (0.7 K).…”