Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5

Abstract

Electronic nematic materials are characterized by a lowered symmetry of the electronic system compared to the underlying lattice, in analogy to the directional alignment without translational order in nematic liquid crystals. Such nematic phases appear in the copper- and iron-based high-temperature superconductors, and their role in establishing superconductivity remains an open question. Nematicity may take an active part, cooperating or competing with superconductivity, or may appear accidentally in such systems. Here we present experimental evidence for a phase of fluctuating nematic character in a heavy-fermion superconductor, CeRhIn (ref. 5). We observe a magnetic-field-induced state in the vicinity of a field-tuned antiferromagnetic quantum critical point at H ≈ 50 tesla. This phase appears above an out-of-plane critical field H* ≈ 28 tesla and is characterized by a substantial in-plane resistivity anisotropy in the presence of a small in-plane field component. The in-plane symmetry breaking has little apparent connection to the underlying lattice, as evidenced by the small magnitude of the magnetostriction anomaly at H*. Furthermore, no anomalies appear in the magnetic torque, suggesting the absence of metamagnetism in this field range. The appearance of nematic behaviour in a prototypical heavy-fermion superconductor highlights the interrelation of nematicity and unconventional superconductivity, suggesting nematicity to be common among correlated materials.

Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions

“…No correction was applied, neither by the thermal expansion of silica, or by strain transfer coefficient, with the notion of displaying just raw data. Note that the magnitude of the anomaly at the antiferromagnetic phase transition T N ≈ 3.8 K is in good agreement with results using capacitive dilatometry [25]. …”

“…Sensing of magnetostriction with single mode SiO 2 FBGs in pulsed magnetic fields is successfully utilized at the National High Magnetic Field Laboratory (NHMFL) with a resolution as good as a few parts per hundred million ( ΔL/L ≈ 10 −8 ) in the best cases. This capability allows for the study of a variety of insulating and metallic condensed matter systems including geometrically frustrated magnets, quantum magnets, multiferroics, and uranium- and cerium-based antiferromagnets [6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30]. Figure 1 shows an example of magnetoelastic effects in pulsed magnetic fields to 60 T at cryogenic temperatures on a sample of uranium dioxide (UO 2 ), which is the most commonly used nuclear fuel.…”

Resistivity near a nematic quantum critical point: Impact of acoustic phonons

“…Recent experiments in several quantum materials have revealed the widespread presence of electronic nematicity, i.e. the lowering of the crystalline point-group symmetry by electronic degrees of freedom [1][2][3][4][5][6][7][8][9][10][11]. Assessing the impact of these nematic degrees of freedom on the normal-state and superconducting properties of these materials remains an important challenge, particularly near a putative nematic quantum critical point (QCP) [12][13][14][15][16][17][18][19][20].…”

Spontaneous gyrotropic electronic order in a transition-metal dichalcogenide

“…Recent theoretical works have highlighted their analogy with classical liquids [19], where a rich set of liquid crystalline phases that exhibit varying degrees of symmetry breaking and transport properties have been observed. A well-studied case is the nematic order [19][20][21], i.e., the spontaneous emergence of rotational anisotropy. In classical liquids, this is known as the nematic liquid crystal, whereas in quantum materials, it has recently been observed in quantum Hall systems, ruthenates, high temperature supercon-3 ductors [19], heavy-fermion superconductors [20], and correlated metallic pyrochlores [21].…”