Research

1. Quantum Information Materials

The idea of realizing and harnessing coherent quantum bits in scalable solid-state environments has attracted widespread attention in the past decade. One of the milestones in the field has been the coherent manipulation of the single nitrogen-vacancy (NV) defect spin in diamond. However, inherent difficulties in growing and controlling the lattice of C diamond pose severe limitations to the use of the NV center for scalable quantum technologies. In close collaboration with experiments, we are searching for analogs to this defect in diverse materials platforms that are technologically important and mature. We proposed a several design schemes to realize NV-analogs in carbides and nitrides, including large-metal ion vacancy complexes and strain-driven formation of spin triplet. Most recently, we are exploring completely new materials paradigms for solid-state qubits, including 2-dimensional van der Waals materials.


Recent publications

2. Quantum spin dynamics

Long coherence times are key to the performance of quantum bits (qubits). In quantum computing, long spin coherence times are necessary for executing quantum algorithms with many gates. Qubits with robust coherence are also ideal systems for developing applications such as collective quantum memories and ultra-sensitive quantum sensors. Using a cluster correlation expansion method, we theoretically predict and understand the quantum decoherence dynamics of a spin qubit in a solid from first-principles. As an example of some of our recent exciting results, we showed that the Hahn-echo coherence time (T2) of electron spins associated with divacancy defects in 4H-SiC reaches 1.3 ms, one of the longest T2 times of an electron spin in a naturally isotopic crystal. Using a first-principles microscopic quantum-bath model, we identified key factors determining the unusually robust coherence. Our results point to polyatomic crystals as promising hosts for coherent qubits in the solid state. More recently, we are investigating the quantum decoherence in diverse heterogeneous and anisotropic materials environments, which were unexplored before in physics. 


Recent publications

3. Computational Physics for Energy and Electronic Materials

In this research direction, we explore the world of materials that are useful for renewable energy, multi-functional electornic and optical devices, and solid-state physical chemistry. Recent research efforts focus on understanding and prediction of novel phases of van der Waals materials, such as complex selenides and sulfides, emergent properties occuring at the correlated oxide heterostructures, and the role of point defects in enhancing conductivity of complex oxides such as BiVO4, which is one of the most promising materials systems for photo-catalytic solar-to-fuel applications.


Recent publications