Related papers: Distinguishing XY from Ising Electron Nematics
The two dimensional electron gas (2DEG) in moderate magnetic fields in ultra-clean AlAs-GaAs heterojunctions exhibits transport anomalies suggestive of a compressible, anisotropic metallic state. Using scaling arguments and Monte Carlo…
An electron nematic is a translationally invariant state which spontaneously breaks the discrete rotational symmetry of a host crystal. In a clean square lattice, the electron nematic has two preferred orientations, while dopant disorder…
Transport experiments in high mobility (110) GaAs heterostructures have been performed at very low temperatures 8 mK. At higher Landau-Levels we observe a transport anisotropy that bears some similarity with what is already seen at…
Electronic nematicity, a correlated state that spontaneously breaks rotational symmetry, is observed in several layered quantum materials. In contrast to their liquid-crystal counterparts, the nematic director cannot usually point in an…
Liquid crystalline phases of matter permeate nature and technology, with examples ranging from cell membranes to liquid-crystal displays. Remarkably, electronic liquid crystal phases can exist in two-dimensional electron systems (2DES) at…
The recently discovered anisotropy of the longitudinal resistance of two-dimensional electrons near half filling of high Landau levels is found to persist to much higher temperatures T when a large in-plane magnetic field B|| is applied.…
Low-temperature, electronic transport in Landau levels N>1 of a two-dimensional electron system is strongly anisotropic. At half-filling of either spin level of each such Landau level the magnetoresistance either collapses to form a deep…
We discuss the behaviour of a quantum Hall system when two Landau levels with opposite spin and combined filling factor near unity are brought into energetic coincidence using an in-plane component of magnetic field. We focus on the…
Nematic superconductors are characterized by an apparent crystal symmetry breaking that results in the anisotropy of the in-plane upper critical magnetic field $H_{c2}$. The symmetry breaking is usually attributed to the strain of the…
We report on recent experimental results from transport measurements with large Hall bars made of high mobility GaAs/AlGaAs heterostructures. Thermally activated conductivities and hopping transport were investigated in the integer quantum…
Magnetotransport properties are investigated for a high mobility Si two dimensional electron systems in the vicinity of a Landau level crossing point. At low temperatures, the resistance peak having a strong anisotropy shows large…
We systematically investigated the in-plane resistivity anisotropy of electron-underdoped $EuFe_{2-x}Co_xAs_2$ and $BaFe_{2-x}Co_xAs_2$, and hole-underdoped $Ba_{1-x}K_xFe_2As_2$. Large in-plane resistivity anisotropy was found in the…
We study phase transitions of coupled two dimensional XY systems with spatial anisotropy and $U(1) \times \mathbb{Z}_2$ symmetry, motivated by spinless bosonic atoms trapped in square optical lattice on the metastable first excited…
Clean two-dimensional electron systems in GaAs/AlGaAs heterostructures exhibit anisotropic collective phases, the quantum Hall nematics, at high Landau level occupancy and low temperatures. An as yet unknown native symmetry-breaking…
Gated GaAs/AlGaAs heterostructures were used to determine the low-temperature behavior of the two-dimensional electron gas near filling factor nu=1/2 in the disorder-magnetic-field plane. We identify a line on which sigma_{xy} is…
The origin of nematicity, i.e., in-plane rotational symmetry breaking, and in particular the relative role played by spontaneous unidirectional ordering of spin, orbital, or charge degrees of freedom, is a challenging issue of magnetism,…
Recent transport experiments have established that two-dimensional electron systems with high-index partial Landau level filling, $\nu^{*} =\nu - \lbrack \nu \rbrack$, have ground states with broken orientational symmetry. In a mean-field…
Electronic nematicity in iron pnictide materials is coupled to both the lattice and the conducting electrons, which allows both structural and transport observables to probe nematic fluctuations and the order parameter. Here we combine…
We consider two-dimensional metals near a Pomeranchuk instability which breaks 90$^\circ$ lattice rotation symmetry. Such metals realize strongly-coupled non-Fermi liquids with critical fluctuations of an Ising-nematic order. At low…
Anisotropic charge transport is observed in a two-dimensional (2D) hole system in a perpendicular magnetic field at filling factors nu=7/2, nu=11/2, and nu=13/2 at low temperature. In stark contrast, the transport at nu=9/2 is isotropic for…