DC Field Science Highlights
Switchable transmission of quantum Hall edge states in bilayer graphene
In the 14 years since its discovery, graphene has amazed scientists around the world with both the ground-breaking physics and technological potential it displays. Recently, scientists from Penn State University added to graphene's gallery of impressive scientific achievements and constructed a map that will aid future exploration of this material. This work is emblematic of the large number of university-based materials research efforts that use the MagLab to explore the frontiers of science.
2D electron-hole "superconductor": Topological excitonic insulator
Decades ago a mechanism was proposed that described a quantum phase transition to an insulating ground state from a semi-metal (excitonic insulator, or EI) using very similar mechanics to those found in the BCS description of superconductivity. The discovery of this transition to an EI in InAs/GaSb quantum wells is striking not only for the long-sought experimental realization of important physics, but also the presence of recently proposed topological behavior.
New magnetic topological semimetal has energy-saving potential
Researchers discover that Sr1-yMn1-zSb2 (y,z < 0.1) is a so-called Weyl material that holds great promise for building devices that require far less power.
Selective mass enhancement close to a quantum critical point
This finding sheds light on the role of quasiparticle mass enhancement near a quantum critical point in one of the leading families of high-temperature superconductors.
Cheaper ways to make strong permanent magnets
New technique transforms common materials into powerful magnets.
Researchers observe exotic superfluid in graphene
Two independent research teams observed same behavior in double bilayer graphene.
Pressure converts an insulator into a metal
The novel behavior could help scientists better understand the mechanisms behind high-temperature superconductivity.
Electrons at "extreme quantum limit" form new kind of state
At high magnetic field, free-flowing particles condense into “puddles.”
New technique for identifying Weyl materials
The work gives physicists a new tool for exploring and understanding a class of materials that could lead to faster electronics.
High field changes phase transitions in “shape-shifting” molecules
With a sufficiently high magnetic field, scientists can manipulate certain phase transitions in some molecules, a discovery that hints at future technological applications.
Crystallization of spin superlattices using pressure and magnetic field
Discovery of a new kind of electron spin superstructure in crystals opens the tantalizing prospect of finding other emergent exotic phases.
New state of matter discovered in single-layer graphene
Discovering previously unobserved quantum states nested inside the quantum Hall effect in a single-layer form of carbon known as graphene, researchers have found evidence of a new state of matter that challenges scientists' understanding of collective electron behavior.
Electron pairs superconduct in NbSe2 layer at high fields
Niobium diselenide is found to retain its superconductivity even under very high magnetic fields.
Magnetic field driven phase transition in underdoped YBCO
Just as all matter may exist in the three famous everyday phases — solid, liquid and gas — complex materials may exist in a combination of subtle phases not apparent to the eye. This finding shows that a class of materials, which all contain copper oxide and are known to exhibit a variety of subtle phases, may have even more complexity than thought. And, in fact, some phases are brought about not by changes in temperature but magnetic field.
Insulator or metal … or, somehow, both at the same time?
Examining the material samarium hexaboride, scientists discover seemingly contradictory properties and an exciting, new mystery for physicists.
Quantum Oscillations in Black Phosphorus Two-dimensional Electron Gas
Black Phosphorus is a layered semiconducting material that can be thinned down to produce atomically thin crystals. These resulting crystals produce a two-dimensional electron gas 2DEG from the resulting quantum confinement of the electrons. Significant differences exist between the physical properties of the atomically thin crystals versus that of the bulk crystals. Zhang and co-workers were able to observe quantum oscillations in black phosphorus allowing the characteristics of the 2DEG in atomically thin crystals to be elucidated.
Anomalous Magnetic Ground-State of the LaAlO3/SrTiO3 Interface Probed by Transport Through Nanowires
The work by Dagan et. al. explores the emergence and coexistence of superconductivity and magnetism at the interface between insulating, non-magnetic LaAlO3 and SrTiO3 nanowires at low temperatures. The effect of the antiparallel magnetic order on the resistance of the 50 nm wide patterned wires follows the form of giant magnetoresistance (GMR) at low applied magnetic fields.
Small hole pocket in the Fermi surface of underdoped YBCO
A team of researchers from Université de Sherbrooke, Laboratoire National des Champs Magnétiques Intenses (LNCMI), University of British Columbia, Canadian Institute for Advanced Research and the National High Magnetic Field Laboratory discovered a previously unobserved portion of the Fermi surface in underdoped YBCO. This discovery provides further evidence to support the picture of the Fermi surface being reconstructed as a result of charge density wave order developing in underdoped YBCO prior to the material entering the superconducting state at lower temperatures.
Quantum Hall Effect in a Three-Dimensional Topological Insulator
The work by Chen et. al. explores the quantum hall effect (QHE) that develops in BiSbTeSe2 at low temperatures and high magnetic fields. BiSbTeSe2 is a topological insulator, meaning it is a bulk insulating material that at low temperatures develops a quantum mechanical state that allows conduction of electrons at the surface similar to a metal. The observation of the QHE in BiSbTeSe2 is further confirmation of the theory governing these unique materials.
Metallic Surface State of Correlated Topological Insulator
SmB6 has been studied for a number of years and its observed behavior had presented investigators with a conflicting set of observations that resisted explanation until recently. The observation of quantum oscillations by Li et. al. in what is a bulk insulator confirm that SmB6 becomes a topological insulator at low temperatures. A topological insulator is a material that develops a unique quantum mechanical state on its surface, which allows electrons to flow in a fashion similar to a metal.
