Lecture at INMA-LMA: Michael Fuhrer
Lecture at INMA-LMA: “The topological transistor as a low-voltage switch”
Michael Fuhrer, from the School of Physics and Astronomy and ARC Centre of Excellence inFuture Low-Energy Electronics Technologies, Monash University, Victoria 3800, Australia, will give a lecture on Friday, 22 July, entitled:”The topological transistor as a low-voltage switch”.
La sesión tendrá lugar a las 12:00 horas en la Sala de conferencias – Edificio I+D+i (Campus Río Ebro).
Summary: The Topological Transistor as a Low-Voltage Switch The impending end of Moore’s Law has prompted a search for a new computing technology with vastly lower energy consumed per operation than silicon CMOS. The recent discovery of topological phases of matter offers a possible solution: a “topological transistor” in which an electric field tunes a material from a conventional insulator “off” state to a topological insulator “on” state, in which topologically protected edge modes carry dissipationless current. This electric field-tuned topological transition has advantages over current MOSFETs: (1) Due to the combined effects of Rashba spin-orbit interaction and electric field control of the bandgap, the topological transistor may switch at lower voltage, overcoming “Boltzmann’s tyranny”[1], and (2) true electric field-controlled switching opens the possibility of using the full power of negative capacitance structures as an electric field amplifier to achieve further reductions in switching voltage[2]. We have studied thin films of Na3Bi grown in ultra-high vacuum by molecular beam epitaxy as a platform for topological electronic devices. When thinned to a few atomic layers Na3Bi is a large gap (>300 meV) 2D topological insulator, and electrical transport measurements demonstrate that the current is carried by helical topological edge modes over millimeter-scale distances[3]. Electric field applied by proximity of an STM tip can close the bandgap completely and reopen it as a conventional insulator[4] demonstrating the basis of electric field-switched topology.
[1] M. Nadeem, I. Di Bernardo, X. Wang, M.S. Fuhrer, and D. Culcer, Nano Letters 21, 3155–3161 (2021).
[2 ]M.S. Fuhrer, M.T. Edmonds, D. Culcer, M. Nadeem, X. Wang, N. Medhekar, Y. Yin and J.H Cole, Proceedings of the 2021 International
Electron Devices Meeting, pp. 38.2.1-38.2.4 (2021).
[3]C. Liu, D. Culcer, Z. Wang, M.T. Edmonds, and M.S. Fuhrer, Nano Letters 9, 6306 (2020).
[4]J.L. Collins, A. Tadich, W. Wu, L.C. Gomes, J.N.B. Rodrigues, C. Liu, J. Hellerstedt, H. Ryu, S. Tang, S.-K. Mo, S. Adam, S.A.
[5]Yang, M.S. Fuhrer & M.T. Edmonds, Nature 564, 390-394 (2018).
