SEMINARIO The topological transistor as a low-voltage switch

El próximo viernes 22 de julio, 12h, el prof. Michael Fuhrer, impartirá la charla “The topological transistor as a low-voltage switch».

Sala de conferencias, LMA edificio I+D+I

Universidad de Zaragoza
Campus Río Ebro
C/ Mariano Esquillor, s/n
50018-Zaragoza

Prof. M.S. Fuhrer

School of Physics and Astronomy, and ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria 3800, Australia

DESCARGA EL ABSTRACT DE LA CHARLA

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: 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”, and 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. 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. Electric field applied by proximity of an STM tip can close the bandgap completely and reopen it as a conventional insulator demonstrating the basis of electric field-switched topology.