Materials for the Quantum Age
QuMat – Materials for the Quantum Age – is a Dutch research program under the gravity initiative. QuMat is a collaboration between researchers in Utrecht, Delft, Groningen, Nijmegen, Eindhoven, and Twente. With a budget of 27 million EUR, QuMat will hire 30 PhD students and postdocs in the years 2022-2023 and another 30 PhD students and postdocs in the years 2027-2028.
Silicon forms the basis of the current information society, instrumental in increasing human welfare. However, there is a never-ending demand for more powerful computing. “Materials for the quantum age” aims to provide proto-type materials with stable coherent quantum states. These will enable classic computing to become much more powerful and at the same time more energy efficient. Moreover, robust quantum states remaining coherent under affordable conditions will allow to upscale powerful quantum computing.
The Materials for the Quantum Age program (QuMat) will design, fabricate and characterize low-dimensional materials with electronic, magnetic or even more complex coherent quantum states. QuMat will further demonstrate materials featuring coherent transport up to room temperature and scalable, affordable materials that host robust qubit states. These materials can open the window to more efficient classic computing and upscaling of quantum computing.
The four pillars of QuMat
Our research program is composed of four pillars directly connected to the distinct nature of the envisaged quantum states: (1) quantum spin Hall insulators with topologically protected quantum channels, (2) two-dimensional magnets in which we aim at quantum control of spins, (3) topological superconductors with exotic quantum states that may serve as robust non-Abelian qubits well protected against the environment, and (4) light-matter interfaces for the interconversion or hybridization of topological quantum states with photons. As complement QuMat will also sharpen and extend the Methods & Techniques that are currently available.
Pillar 1
Electronic materials with coherent quantum channels by strong topological protection
Pillar leaders: Daniel Vanmaekelbergh and Zeila Zanolli
Pillar 1 studies quantum spin Hall insulators with a large topological gap; the helical states at the edge of these materials are strongly protected, holding promise to remain coherent up to practical temperatures. In the two (first-term) research projects we will develop 2D hybrid materials based on Bi-ene and WTe2 . We will use advanced synthesis methods to fabricate well-defined hybrid architectures, use proximity effects to increase the topological gap, study all physical aspects of the quantum channels, and fabricate devices to study coherent or coherence-mediated transport.
Highlight after first term: Demonstration of coherent quantum edge channels, up to liquid nitrogen temperature. Pillar 2
Quantum control of spins
Pillar leaders: Bart van Wees and Rembert Duine
Pillar 2 studies 2D magnets that show coherent spin waves (magnons) and more complex magnetic excitations. The three (first-term) research projects focus on topological magnonics, the control of spins to the quantum limits in length and time, and complex magnetic order beyond magnons. In terms of materials, we focus on magnets with heavy-elements, e.g. CrI3 , Cr2 Ge2Te6 , … proximitized with other materials, such as WTe2, to enhance spin-orbit coupling. A main objective is to understand the interplay between spin-orbit coupling, several types of exchange interactions, and external stimuli, in order to control the spins at nm length scale.
Highlight after first term: Demonstration of topological magnons in quantum edge channels. Pillar 3
Topological superconductivity
Pillar leaders: Alexander Brinkman and Erik Bakkers
Pillar 3 studies hybrid materials in which topological superconductivity is induced by
proximity. In the first project, PbTe- and Ge-superconductor hetero-wires and wells with atomically exact crystal structures and interfaces are aimed at. Both the materials and the recently developed in-situ fabrication technology constitute steps forward with respect to the III-V nanowire systems reported by Microsoft. In the second and third project, the hybrid quantum spin Hall materials that are featured in Pillar 1 will be used to induce robust topological superconductivity in the edge channels. Furthermore, we aim to fully analyze all aspects of the zero-energy states with new types of spectroscopy.
Highlight after first term: Demonstration of topological superconductivity with a robust and hard superconductive gap
Pillar 4
Topological light-matter interfaces
Pillar leaders: Kobus Kuipers and Caspar van der Wal
Pillar 4 develops and studies the conversion of topological quantum states (magnons, excitons) into (wave guide) photon states, and hybridization of topological quantum states with light. For topological exciton-light interfaces, we will start with 2D Bi2Se3 systems (project 1). The 2D magnetic materials of Pillar 2 form the basis for magnon/light interfaces (project 2). The physics of topological light-matter conversion must be fully understood and used to fabricate efficient interfaces between topological materials and wave guides.
Highlight after first term: Controlled and efficient conversion of magnons into photons and vice versa.
Methods & Techniques
Pillar leaders: Cristiane de Morais Smith and Alexander Khajetoorians
The research goals of the 4 pillars and the demonstrators can only be reached by a concerted effort of a broad team of collaborating top scientists, with expert skills in methods and techniques of theory, synthesis and characterization. On some occasions it will be required to sharpen and extend the methods and techniques that we have available now. This will be achieved by collaborative efforts of the PhDs/PDs working in the pillars supported by the available expertise and equipment in the consortium; for some very generally used methods we have defined separate projects.
QuMat foresees in regular Method & Technique meetings to discuss technical topics and find ways to sharpen theory or experimental tools. This work will be led and organized by the leaders of the M&T section.