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Jiayi Zhu

My research is mainly on studying valley polarization controlling in different transition metal dichalcogenides (TMD) heterostructures and exploring TMD device structures with higher efficiency. Valley pseudospin is an analogy to spin, giving rise to a new quantum index for people’s manipulation and it has potential application in quantum computing in the future. 2D TMD is the most promising candidate material for useful valleytronic application from its strong excitonic effect and spin-valley locking properties. In TMD heterostructure, the strongly unbalanced valley polarization can be generated with circularly polarized light of minimal power. For example, in WSe2/MoSe2, people can use as low as a few nanowatt...

Chun-Chih Tseng

Introducing the magnetic and spin-orbit coupling into graphene in proximity to dissimilar crystals has been extensively studied to realize exotic emergent physics. They include the dissipationless edge transport in quantum anomalous Hall effect and the efficient spin accumulation due to exchange splitting of Dirac cone in graphene. My research will focus on the investigation of these proximity effects in graphene on van der Waal magnets and topological insulators by the transport characterization. This study will help to gain the better understanding in engineering graphene properties and might benefit the low energy consumption application in the future Advisor: Matthew Yankowitz - Physics...

Heonjoon Park

Two-dimensional semiconductor moiré superlattices are a powerful platform for engineering correlated electronic phenomena. My research focuses on the exploration of the extended Bose-Hubbard model of exciton lattices in twisted transition metal dichalcogenide moiré materials. I employ optical techniques to probe emergent phases in interacting opto-moiré quantum matter. Advisor: Xiaodong Xu - Physics...

Eric Lester

My research aims to study electrical transport in two-dimensional (2D) materials and 2D heterostructures. Particularly, I am interested in the 2D topological insulator WTe2 and its complex interactions with graphene. I have also been developing a two-axis rotator for use on a dilution refrigerator to study magnetic anisotropy of low-dimensional materials below 1 Kelvin. My research on highly anisotropic materials like WTe2 is primarily concerned with fundamental physical mechanisms, and it is my hope that by gaining a better understanding of these materials, new applications can be discovered as well. These include highly efficient, atomically-thin thermoelectric devices for use in energy and heat efficient microelectronic...

Jonathan DeStefano

I utilize materials synthesis and thermodynamic, magnetometric, and transport measurements to study materials with non-trivial topological band structures. These materials host surface states which hold promise for applications in a wide variety of fields including quantum computing and next-generation electronics. Of particular interest to me is the interplay of these surface states with magnetism or superconductivity. I hope to develop a deeper understanding of these materials, thus pushing them closer to being used in technical applications. Advisor: Jiun-Haw Chu - Physics...

Jared Abramson

Approximately 250,000 metric tons of nuclear waste currently sit in short term storage around the world with the US accounting for over 90,000. Deep geologic repositories (DGRs) are widely considered the best solution to dispose/storge this waste. The general design of DGRs is widely agreed upon, but some specific aspects optimum design is still uncertain and understudied. One of these aspects is the cement that is used as containment and backfill in some DGR designs, including the design that was implemented in the US at Yucca Mountain until recently. My research focuses on studying different cement formulations to understand how the cement will contribute...

Tharindu W. Fernando

I will use computational and theoretical approaches to understand and predict topological effects of materials in their optically excited states. Currently, I am wrapping-up an investigation on a novel interband index T for 2D systems (such as transition metal dichalcogenides). We showed that T may provide gauge-invariant excitonic optical selection rules and help characterize valley topology in excited states. Next, I will develop robust DFT-based computational schemes to calculate T in other materials beyond tight-binding frameworks. I will simultaneously study T in non-Hermitian systems; which are realistic quantum systems with gain and loss due to interactions with optical fields and environments. I am interested...

John Cenker

Two-dimensional van der Waals crystals hold great promise for future devices due to their atomically thin nature and the consequent unique emergent physics. Furthermore, their pristine crystal lattices should make them extraordinarily robust to external stresses such as strain. My research focuses on developing new ways to apply strain to 2D materials to drive phase transitions which can be harnessed for future device applications. For example, applying strain to atomically thin magnets to drive magnetic phase transitions. This research could enable energy-efficient, ultrathin memory bits which can be written purely by an applied voltage to the strain cell. Advisor: Xiaodong Xu - Physics...

Christian Pederson

Simulating novel materials with the desired range of properties for efficient solar energy collection, or storage is computationally intractable with classical computers.  Quantum computers and simulators are the only known devices that can efficiently tackle these problems, yet are plagued by the experimental challenges of scaling up sensitive quantum systems. I will investigate an integrated photonics platform based on point defects in diamond. Significant challenges remain, but integrated devices have a clear path to scalability since they build upon existing semiconductor fabrication methods. Recent work demonstrated that a particular defect, the silicon-vacancy(SiV) center, could be created nanometers from the surface of diamond without compromising its...

Jiaqi Cai

One of the CEI missions is to develop next generation’s energy saving technologies. To date, the information processing is accompanied by inevitable energy dissipation in devices caused by impurity scattering. Very recently, a new phase of matter, named as magnetic topological insulator (MTI), emerged as a promising platform to develop dissipationless electronics, where carriers transmit along the edge of the devices without any energy loss. This dissipationless property is ensured by the topological nature which enables the edge conduction to be immune from bulk impurity scattering. What’s more, the interplay of magnetism and non-trivial topology in MTI makes the electronic state controllable, enabling the devices to...

Kyle Hwangbo

My research will focus on the investigation of the inherent properties and the tunability (by optical and electronic means) of a new intrinsic magnetic semiconductor, NiPS3. This material is the first example of semiconductor quantum well (QW) with intrinsic antiferromagnetic order. As the semiconductor QWs formed the foundation for our modern solid-state device technologies, we envision that these type of new materials with intrinsic magnetic order may lead to new energy efficient spintronic and optoelectronic devices, such as low energy consumption data storage and computing. These application potentials are well in-line with the mission of the Clean Energy Institute and may be an important...

Jordan Fonseca

Due to the explosive increase in the amount of information generated throughout our daily lives, one of the key challenges of our society will be storing and manipulating data with high energy efficiency. One promising approach to solving this grand energy consumption challenge is exploring new data storage and computing technologies based on ultra-thin antiferromagnetic materials. The promise of antiferromagnetism lies in the absence of net magnetization, which increases the achievable density of storage, while the large exchange interactions could enable operation speeds in the terahertz regime. Supported by the CEI award, I will apply a variety of optical techniques to probe the exotic...