Partnerships for Research and Education in Materials

We have developed new state of the art density matrix renormalization group (DMRG) and transport codes, which can deal with large electron systems with interaction. Right two figures represent some results we obtained with our collaborators.

On the right side, top panel shows our quantum phase diagram for Haldane honeycomb model with spin orbit interaction. It shows that using gate voltage V one can tune into quantum Hall effect (QAHE) by splitting quantum spin Hall effect (QSHE) for system without time reversal symmetry. Bottom panel shows the entanglement gap extrapolates to finite value at thermodynamic limit demonstrating topological order of the 5/2 system.

Electrical transport measurements on a suspended ultra-low-disorder graphene nanoribbon (GNR) with nearly atomically smooth edges have been carried out by Zhixian Zhou and co-workers at Wayne State University that reveal a high mobility exceeding 3000 cm2 V−1 s−1 and an intrinsic band gap.

The objective of the PREM program is to expand and strengthen the research and educational activities of the multidisciplinary W. M. Keck Computational Materials Theory Center (CMTC) at California State University Northridge (CSUN), a Hispanic-serving institution, by forming a formal and long-term collaborative relationship with the Princeton Center for Complex Materials (PCCM). The goals of [...]

The ability to perform quantum simulations of materials properties over length scales that are relevant to experiments represents a grand challenge in computational materials science.

We study the non-abelian quantum Hall effect, a spectrum gap is established to protect topological degenerating Pfaffian states, which may have novel applications in quantum computing.

We reproduce the recent experimentally discovered odd integer quantum Hall effect in graphene The bottom image reveals a stripe order and symmetry broken state in higher Dirac Landau levels Small projects involved in this research are used in a new course taught at CSUN by Dr. Sheng (PHYS 466) for undergraduate students, where density of [...]

When a spin polarized current passes through a magnetic multilayer structure, it can transfer spin angular momentum from one ferromagnet to another, and hence exert a torque on the magnetic moments of the electrodes. At sufficiently high current densities, this spin transfer torque can even reverse the magnetization of an individual domain. We predicted an [...]