Ph.D. 1984 Northwestern University

e-mail: vignaleg@missouri.edu

Author

1. Quantum Theory of the Electron Liquid

2. The Beautiful Invisible: Creativity, Imagination, and Theoretical Physics

Research Summary

Density functional theory, Spintronics, Quantum many body theory, Theory of 2-dimensional materials.

Prof. Vignale studies the behavior of many-electron systems in strong external fields, confined geometry and/or reduced dimensionality. These systems are usually realized in artificial microstructures, such as quantum wells at the interface of two semiconductors, quantum dots, and multilayers structures, in the presence of strong magnetic fields, and/or time-dependent electromagnetic fields. The focus of Vignale’s research is understanding the effects that arise from the interaction between the electrons . For the theoretical description of interacting electrons he developed a formalism known as “current-density functional theory” (CDFT), which expresses the properties of the electron system in terms of its current density.

Vignale’s work on time-dependent CDFT shows that the electronic dynamics is equivalent, in the appropriate macroscopic limit, to a generalized hydrodynamics, with viscoelastic coefficients determined from properties of the homogeneous electron gas. This theory has suggested a novel approach to the dynamics of a two-dimensional electron gas (2DEG) in a very strong magnetic field. This theoretical description is consistent with the results of recent tunneling experiments at the edge of the 2 DEG. Vignale and his group have also worked on the problem of “Coulomb drag” and superfluidity in spatially separated, interacting two-dimensional layers containing electrons and holes respectively. A new signature of superfluidity has been proposed, and strategies to facilitate condensation in realistic systems have been devised.

In the past ten years Vignale's research has focused on spin-charge interconversion phenomena in 2D electronic systems and topological surface states, such as the spin Hall effect, the spin-galvanic effect and their inverses, and various mechanisms of magnetoresistance.

Selected Publications (Last 5 years)

“Non local Anomalous Hall Effect”, Steven S. -L. Zhang and G. Vignale, arXiv:1512.04146 (2015), Phys. Rev. Lett. 116, 136601 (2016).

“Hall viscosity and electromagnetic response of electrons in graphene”, M. Sherafati, A. Principi, and G. Vignale, arXiv:1605.02782, Phys. Rev. B 94, 125427 (2016)
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“Functional theories of thermoelectric phenomena”, F. G. Eich, G. Vignale, and M. Di Ventra, arXiv:1607.05464, Journal of Physics: Condensed Matter 29, 063001 (2017).

“Theory of unidirectional spin Hall magnetoresistance in heavy metal/ferromagnetic metal bilayers”, S.-L. Zhang and G. Vignale, arXiv:1608.02124, Phys. Rev. B 94, 140411 (R) (2016)

“Theory of current-induced spin polarization in an electron gas”, C. Gorini, A. Maleki, Ka Shen, I. V. Tokatly, G.Vignale, and R. Raimondi, arXiv:1702.04887, Physical Review B 95, 205424 (2017).

“Bilinear magneto-electric resistance as a probe of three-dimensional spin texture in topological surface states”, Pan He, Steven S.-L. Zhang, Dapeng Zhu, Yang Liu, Yi Wang, Jiawei Yu, G.Vignale and Hyunsoo Yang, arXiv:1706.09589, Nat. Phys. 14, 495 (2018).

://doi.org/10.1038/s41567-017-0039-

“Effective mass of quasiparticles from thermodynamics”, F. G. Eich, Markus Holzmann, and G. Vignale, arXiv:1704.04076, Phys. Rev. B 96, 035132 (2017).

“U(1)xSU(2) gauge invariance made simple for density functional approximations”, S. Pittalis, G. Vignale, F. G. Eich, arXiv:1704.07304, Phys. Rev. B 96, 035141 (2017).

"Chiral surface and edge plasmons in ferromagnetic conductors", Steven S.-L. Zhang and G. Vignale, arXiv:1804.06967, Phys. Rev. B 97, 224408 (2018).

"Observation of Out-of-Plane Spin Texture in a SrTiO3(111) two-dimensional electron gas, Pan He, S. McKeown Walker, Steven S.-L. Zhang, F. Y. Bruno, M. S. Bahramy, Jong Min Lee, Rajagopalan Ramaswamy, Kaiming Cai, Olle Heinonen, Giovanni Vignale, F. Baumberger, and Hyunsoo Yang, arXiv:1806.01533, Phys. Rev. Lett 120, 266802 (2018).

"The Impossible spin and its applications", G. Vignale and Steven S.–L Zhang, Il Nuovo Saggiatore 34, N. 5-6 (2018) pp. 15-26.

"Disorder-enabled hydrodynamics in monolayer graphene, M. Zarenia, A. Principi, and G. Vignale, 2D Materials 6, 035024 (2019), arXiv:1811.08914.

"Breakdown of the Wiedemann-Franz law in AB-stacked bilayer graphene, Mohammad Zarenia, Giovanni Vignale, Thomas Benjamin Smith, Alessandro Principi, Physical Review B 99, 161407 (Rapid Communications), 2019, arXiv:1901.05077.

Pan He, Steven S.-L. Zhang, Dapeng Zhu, S. Shi, O. Heinonen, G. Vignale and Hyunsoo Yang, "Nonlinear planar Hall effect in a non-magnetic topological insulator, Phys. Rev. Lett. 123, 016801 (2019).

"Superconductivity from collective excitations in magic angle twisted bilayer graphene", G. Sharma, M. Trushin, O. P. Sushkov, G. Vignale and S. Adam, arXiv:1909.02574, Physical Review Research 2, 022040 (R) (2020).

"Hall diffusion anomaly and transverse Einstein relation", J. C. W. Song and G. Vignale,, arXiv:2007.10373.

"Thermal transport in compensated semimetals: Effect of electron-electron scattering on Lorenz ratio", M. Zarenia, A. Principi, and G. Vignale, Phys. Rev. B 102, 214304 (2020).

"Orbital Hall effect as an alternative to valley Hall effect in gapped graphene", S. Bhowal and G. Vignale, arXiv:2103.03148, Phys. Rev. B. 103, 195309 (2021).

"Collective excitations and quantum incompressibility in electron-hole bilayers", S. De Palo, P. E. Trevisanutto, G. Senatore, and G. Vignale, arXiv:2107.12063, Phys. Rev. B 104, 115165 (2021).