Colloquium: Liang Fu, MIT

There will be a formal presentation of the Anatoly Larkin Award at the start of Colloquium.

Professor Fu's research is concerned with the application of topology in solid state physics to predict new phases of matter and topological materials.

Diodic quantum materials

Abstract: The p-n junction is the key building block of modern microelectronics that underlies diodes and transistors. In recent years, it has been found that certain quantum materials can have a direction dependent electrical resistance and thus exhibit an intrinsic diode effect without any junction. In this talk, I will first describe diodic superconductors that exhibit zero (nonzero) resistance in the forward (backward) direction. Such superconducting diode effect generally appears when Cooper pairs in the ground state have finite center-of-mass momentum, as in the Larkin-Ovchinnikov-Fulde-Ferrell superconductor. Next, I will describe noncentrosymmetric conductors that exhibit a nonreciprocal Hall effect at zero magnetic field, with the transverse current quadratic in the applied voltage. This intrinsic nonreciprocity is a fundamental material property that originates from the quantum geometry of itinerant electron states in crystals. Potential applications of diodic quantum materials in high-frequency (THz) and low-power electronics will be discussed.