Center for Molecular Magnetic Quantum Materials (M2QM)

Cloud computing and ultra-high performance computing consume enormous amounts of electrical power to cool the machines. The ones and zeros of binary arithmetic are switched physically by moving electrons through circuits. When billions of circuits all move electrons in a modern computer, there is enormous power consumption, hence enormous waste heat. But what if we could represent the binary numbers with a switchable physical phenomenon that does not require moving charges in an electric field? That would drastically reduce heating. It should be possible. After all, magnetic hard drives use switchable magnetic polarization (up and down) to store digital bits. Switching magnetic polarization does not involve moving charges. But magnetic memory devices are difficult to integrate into a circuit because reading and writing the bits usually requires application of a magnetic field.The central quest of the M2QM project is to achieve such magnetic switching at molecular scale and to achieve switching and reading with an electric field. This would have a more profound outcome than reduction of heating. It would enable quantum computing – working with molecular states that are both one and zero and in-between. This is the shift from 'bits' to 'qubits'. The molecular state that is critical to its magnetism is called the 'spin state'.The first term of M2QM has demonstrably moved the science of molecular magnets (MMs) towards the goal of quantum information applications. We identified new qubit candidates for two-qubit gate operations and showcased the viability of integrating MMs on surfaces for addressing and read-out. We demonstrated the impact of theory both in the modeling and in the discovery of MM candidates and in proposing new types of quantum information control in such systems.However, it is still a long journey before we can have a desktop quantum computer or drive an iPad using quantum chips. This leads to the concept of 'quantum materials'. In them, quantum mechanics is important not just for holding the material together and giving it properties, but also for having usable atomic and molecular-scale phenomena. In the new funding period, we organized three thrust areas for fundamental science. The first is to understand how and how long it takes for a physical system to lose its critical quantum characteristics. We search for molecular types that maintain their quantum nature for times longer than the device operational time. The second thrust investigates couplings of magnetic and electronic properties ('ME' couplings) in molecular quantum materials. We look for MMs with strong ME couplings that give high tunability, that is, use of a magnetic field to change electric properties and vice versa. The third seeks to control MM films and substrate interactions, for example, to achieve quantum tunneling based control. All of this research is supported by an intense theoretical and computational effort to simulate the quantum properties of individual molecules and discover candidate systems through machine-learning, high throughput studies.The eight theorists and computationalists on the M2QM team will build models to simulate spin state control in molecules alone, on surfaces and in junctions, and ME couplings. The seven experimenters will synthesize MMs and characterize them, then assemble them onto substrates and probe their controllability and responses. This research will continue to go a long way to answering two key Department of Energy questions: 'How do we control material processes at the level of electrons? and 'How do we design and perfect atom- and energy-efficient synthesis of revolutionary new forms of matter with tailored properties?' M2QM thus will lay the ground work for molecular magnetic quantum materials for quantum information systems and advanced, low-power digital devices.