HELICOMBX · Quantum spin Hall insulator with two dimensional crystals
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2015-06-01 → 2017-05-31
- EU contribution
- €173,076
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
Lines connect the coordinator with its partners.
Results in brief
Quantum spin Hall insulator with two dimensional crystals
Graphene offers opportunities to generate novel electronics based on dramatically high mobility carriers and authentic atomically thin two dimensional exposed electron gas, compatible with scalability in recent electronics devices. In condensed matter physics, the distinct band structure (the Dirac cones) which contributes to the relativistic motion of electrons and additional degrees of freedom such as valley spin and pseudospin are examples of attractive phenonema unique to graphene, and many other unexpected properties have been reported both theoretically and experimentally. Although graphene seems a perfect material in terms of the richness of novel physical phenomena, it lacks one important property; spin-orbit interaction (SOI). Due to small atomic number of carbon, SOI of graphene is as small as 24 micro eV. SOI becomes more and more important in recent condensed matter physics, and many intriguing phenomena that is actively debated such as the spin Hall effect (SHE) or topological insulators derive from SOI. In this project, we attempt to enhance SOI in graphene in several different ways. First, we carry out adatom depositions on top of graphene. Adatoms of elements with strong SOI are theoretically expected to induce strong SOI in graphene via electron transfer between them. Subsequently, we also fabricate heterostructures with graphene and another two-dimentional van der Waals material; transition metal dichalcogenides (TMDs). TMDs are composed of heavy elements such as Mo or W, and their intrinsic SOI is much stronger than that of graphene. Electronic interaction between them can induce strong SOI in graphene. Based on the outcomes of these processes, our final goal of the project is to observe the quantum spin Hall (QSH) state in graphene. Strong SOI in graphene make it possible to apply graphene to spintronics as an efficient spin-charge converter via the SHE. The QSH state is characterized as the dissipationless channels. These effects are by itself interesting in regard to physics, but also significant as building blocks for novel electronic devices. The outcomes of our project are definitely useful to develop future electronics.
Data: CORDIS, © European Union
Project objective
Dissipationless electrical transport is a key paradigm to reduce energy consumption in our society. Recent advancements incondensed matter physics have revealed that there exist ballistic transport channels at the surface or the edge of topologicalinsulators. These states are preserved by time-reversal symmetry and robust against back scattering. Exploiting topologicalinsulators is therefore a major step for future nondissipative nanoelectronics.Nevertheless, such a topological phase of matter has been discovered in very few kinds of materials so far. Most of theexisting materials are difficult to fabricate, which limits scientific endeavor to explore their properties and also futureapplication. Recently, several theoretical studies have demonstrated that atomically thin graphene or other two dimensionalcrystals may become two dimensional topological insulators (quantum spin Hall insulators) by inducing large spin-orbitinteraction. These materials are rich of novel physics and attract growing attention in their own right. Moreover, they areeasy to prepare by mechanical exfoliation, which facilitates to apply them to real nanoelectronics devices.HELICOMBX is the first project which aims at establishing a basis for dissipationless electronics and spintronics withgraphene and transition metal dichalcogenides and unifying physics in topological phase, spintronics and two dimensionalcrystals. The project is divided into three parts. First we will induce large spin-orbit interaction in graphene by adatomsdeposition and heterostructures construction with transition metal dichalcogenides. Spin-orbit interaction of each system isthen measured by magnetotransport measurements. Second we will exploit these functionalized two dimensional crystals forspintronics devices. As the final part, quantized conductance will be measured as a signature of the edge states, and we willintegrate it into Josephson junctions to observe the Majorana fermions.
Original text from CORDIS.
Participants
- CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS · ParisCoordinatorFrance
Links
Data: CORDIS, © European Union