Publications by authors named "A K Geim"

Unconventional superconductivity, where electron pairing does not involve electron-phonon interactions, is often attributed to magnetic correlations in a material. Well known examples include high-T cuprates and uranium-based heavy fermion superconductors. Less explored are unconventional superconductors with strong spin-orbit coupling, where interactions between spin-polarised electrons and external magnetic field can result in multiple superconducting phases and field-induced transitions between them, a rare phenomenon in the superconducting state.

View Article and Find Full Text PDF
Article Synopsis
  • - Two-dimensional (2D) crystals are promising materials for proton conduction, as they can selectively allow protons to pass while blocking larger atoms and molecules.
  • - Research shows that vacancy-rich titania monolayers demonstrate high proton conductivity, exceeding 100 S/cm at 200°C, while preventing helium permeability, meeting industry benchmarks.
  • - The exceptional proton transport in these monolayers is due to a high density of titanium vacancies, which enables them to function like ultra-fine sieves, indicating their potential for hydrogen technology applications.
View Article and Find Full Text PDF

Coulomb drag between adjacent electron and hole gases has attracted considerable attention, being studied in various two-dimensional systems, including semiconductor and graphene heterostructures. Here we report measurements of electron-hole drag in the Planckian plasma that develops in monolayer graphene in the vicinity of its Dirac point above liquid-nitrogen temperatures. The frequent electron-hole scattering forces minority carriers to move against the applied electric field due to the drag induced by majority carriers.

View Article and Find Full Text PDF

The ongoing efforts to optimize rechargeable Li-ion batteries led to the interest in intercalation of nanoscale layered compounds, including bilayer graphene. Its lithium intercalation has been demonstrated recently but the mechanisms underpinning the storage capacity remain poorly understood. Here, using magnetotransport measurements, we report in-operando intercalation dynamics of bilayer graphene.

View Article and Find Full Text PDF

Understanding and controlling the electrical properties of solution-processed 2D materials is key to further printed electronics progress. Here, we demonstrate that the thermolysis of the aromatic intercalants utilized in nanosheet exfoliation for graphene laminates allows for high intrinsic mobility and the simultaneous control of doping type (- and -) and concentration over a wide range. We establish that the intraflake mobility is high by observing a linear magnetoresistance of such solution-processed graphene laminates and using it to devolve the interflake tunneling and intralayer magnetotransport.

View Article and Find Full Text PDF