Theory

* Currently, our center has 3 theory teams as introduced below.
             
Correlated Quantum Matter Theory  /  Prof. Bohm-Jung Yang                            

  
     Our research group studies a broad class of theoretical problems about correlated topological quantum matter by using various theoretical tools including analytic quantum field theory and numerical methods. Currently, we are focusing on new emergent quantum physics originating from the nontrivial interplay between electron correlations and bulk topological properties such as quantum critical phenomena in topological media, interacting Weyl/Dirac semimetals, 5d transition metal oxides, frustrated quantum magnets, etc. Our aim is to search for unconventional quantum states of matter beyond the conventional paradigms and theoretically design novel functional materials.


[Selected Publications]                             

* Large anomalous Hall current induced by topological nodal lines in a ferromagnetic van der Waals semimetal
* Unconventional topological phase transition in two-dimensional systems with space-time inversion symmetry
* Emergent non-Fermi liquids at the quantum critical point of a topological phase transition in two dimensions
* Magnetic-field-induced insulator-semimetal transition in a pyrochlore Nd2Ir2O7
* Classification of stable three-dimensional Dirac semimetals with nontrivial topology
Quantum criticality of topological phase transitions in 3D interacting electron systems
Emergent topological phenomena in thin films of pyrochlore iridates
Topological protection of bound states against the hybridization
Theory of topological quantum phase transitions in 3D non-centrosymmetric systems

First-principles Theory  /  Dr. Choong Hyun Kim                 
                                                                                                                      
     Our team, led by Dr. Choong Hyun Kim, is the first-principles theory team to be established within the IBS Center for Correlated Electron Systems. A key element of our team is the study of emerging phenomena arising from the interplay between correlations and spin-orbit-coupled electronic structure. Utilizing first-principles-based electronic structure calculation methods, we aim to understand and discover novel physical properties of correlated oxides and related systems. Especially, our main interest is in the correlated system with strong spin-orbit coupling effects.


[Selected Publications]                                                                                    

* Spin-orbital-entangled Jeff =1/2 state in 3d transition metal oxide CuAl2O4
* Topological Superconductivity in Metal/Quantum-Spin-Ice Heterostructures
* Interplay of spin-orbit interactions, dimensionality, and octahedral rotations in semimetallic SrIrO3
* Orbital chirality and Rashba interaction in magnetic bands
* Topological quantum phase transition in transition metal oxide Na2IrO3



Computational Materials Theory  /  Dr. Se Young Park                                                                         
                                                                                                                     
     The computational materials theory team focuses on understanding the emergent phenomena using various computation methods. The team established within the IBS-CCES is led by Dr. Se Young Park. Our immediate interest is to understand and predict the electronic, transport, optical properties of the bulk complex oxides and oxide heterostructures. Our computational methods are based on first-principles density functional theory capable of including both electronic and ionic degree of freedom to predict the properties of the materials without bias and numerical many-body techniques such as dynamical mean-field theory solving effective Hamiltonian to investigate the many-body effects.


[Selected Publications]                                                                                                            

* Charge-order-induced ferroelectricity in LaVO3/SrVO3 superlattices
* Flux states and topological phases from spontaneous time-reversal symmetry breaking in CrSi(Ge)Te3-based systems
* Charge density distribution and optical response of the LaAlO3/SrTiO3 interface