Magnetic effect without a magnet

Electric current is deflected by a magnetic field—in conducting materials, this leads to the so-called Hall effect. This effect is often used to measure magnetic fields. A surprising discovery has now been made at TU Wien, in collaboration with scientists from the Paul Scherrer Institute (Switzerland), McMater University (Canada), and Rice University (U.S.): an exotic metal made of cerium, bismuth and…

The observation of Bloch ferromagnetism in composite fermions

Composite fermions are exotic quasi-particles found in interacting 2-D fermion systems at relatively large perpendicular magnetic fields. These quasi-particles, which are composed of an electron and two magnetic flux quanta, have often been used to describe a physical phenomenon known as the fractional quantum Hall effect. …

The Hall effect links superconductivity and quantum criticality in a strange metal

Over the past few decades, researchers have identified a number of superconducting materials with atypical properties, known as unconventional superconductors. Many of these superconductors share the same anomalous charge transport properties and are thus collectively characterized as “strange metals.” …

Discoveries of high-Chern-number and high-temperature Chern insulator states

The Quantum Hall effect (QHE) is one of the most important discoveries in physical sciences. Due to the one-dimensional (1-D) dissipationless edge states, QHE exhibits exotic transport properties with quantized Hall resistance of h/νe2 and vanishing longitudinal resistance. Here, h is Planck’s constant, ν is Landau filling factor and e is electron charge. QHE usually originates from the formation of remarkable…

Quantum hall effect ‘reincarnated’ in 3-D topological materials

U.S. and German physicists have found surprising evidence that one of the most famous phenomena in modern physics—the quantum Hall effect—is “reincarnated” in topological superconductors that could be used to build fault-tolerant quantum computers. …

Quantum anomalous Hall effect in intrinsic magnetic topological insulator

Nontrivial band topology can combine with magnetic order in a magnetic topological insulator to produce exotic states of matter such as quantum anomalous Hall (QAH) insulators and axion insulators. An aim of condensed matter physics is to find new materials with useful properties and apply quantum mechanics to study them. The field has allowed physicists to better understand the uses of…