Publications (48)
Field-controlled quantum anomalous Hall effect in electron-doped CrSiTe monolayer: a first-principles prediction
Sungmo Kang, Seungjin Kang, Heung-Sik Kim +1
We report Chern insulating phases emerging from a single layer of layered chalcogenide CrSiTe, a transition metal trichacogenides (TMTC) material, in the presence of charge d…
Activating magnetoelectric optical properties by twisting antiferromagnetic bilayers
Kunihiro Yananose, Paolo G. Radaelli, Mario Cuoco +2
Twisting in bilayers introduces structural chirality with two enantiomers, i.e., left- and right-hand bilayers, depending on the oriented twist angle. The interplay between this gl…
Collinear and non-collinear spin ground state of wurtzite CoO
Myung Joon Han, Heung-Sik Kim, Dong Geun Kim +1
Collinear and non-collinear spin structures of wurtzite phase CoO often appearing in nano-sized samples are investigated using first-principles density functional theory calculatio…
Counter-intuitive Ferroelectric Property And Non-negligible Orbital Magnetic Moment In Cr/Cu Based Perovskite Metal-Organic Frameworks
Kunihiro Yananose, Jaejun Yu
Metal-organic frameworks (MOFs) possess a hybrid nature, combining the inorganic properties from the metal ions and the organic properties from the molecular linkers. Stroppa, \tex…
Pseudogap formation of four-layer BaRuO and its electrodynamic response changes
Y. S. Lee, J. S. Lee, K. W. Kim +5
We investiaged the optical properties of four-layer BaRuO, which shows a fermi-liquid-like behavior at low temperature. Its optical conductivity spectra clearly displayed the…
Large in-plane deformation of RuO6 octahedron and ferromagnetism of bulk SrRuO3
Sanghyun Lee, J. R. Zhang, S. Torii +6
SrRuO3 is a ferromagnetic metal with several unusual physical properties such as zero thermal expansion below Tc, so-called Invar behavior. Another anomalous feature is that the a-…
Topological Quantum Phase Transition in 5 Transition Metal Oxide NaIrO
Choong H. Kim, Heung Sik Kim, Hogyun Jeong +2
We predict a quantum phase transition from normal to topological insulators in the 5 transition metal oxide NaIrO, where the transition can be driven by the change of th…
Breakdown of half-metallic ferromagnetism in zinc-blende II-V compounds
Yun Li, Jaejun Yu
We investigated the electronic and magnetic properties of a series of zinc-blend II-V compounds by carrying out density-functional-theory calculations including spin-orbit coupling…
Spin Triplet Excitations for a Valence Bond Solid on the Kagome Lattice
Bohm-Jung Yang, Yong Baek Kim, Jaejun Yu +1
One of the most promising candidate ground states for the quantum antiferromagnetic Heisenberg model on the Kagome lattice is the valence bond solid (VBS) with a 36-site unit cell.…
Role of oxygen vacancy in the spin-state change and magnetic ordering in SrCoO
Jinyoung Lim, Jaejun Yu
We present the first-principles investigation of the structural, electronic, and magnetic properties of SrCoO () to understand the multivalent nature of C…
A Scaling Behavior of Spectral Weight Changes in Perovskite Manganites La_{0.7-y}Pr_{y}Ca_{0.3}MnO_3
K. H. Kim, J. H. Jung, D. J. Eom +3
Optical conductivity spectra of La_{0.7-y}Pr_{y}Ca_{0.3}MnO_3 were systematically investigated. For metallic samples, the spectral weight below 0.5 eV, whose magnitude can be repre…
Optical Investigations of Charge Gap in Orbital Ordered La1/2Sr3/2MnO4
J. H. Jung, J. S. Ahn, T. W. Noh +5
Temperature and polarization dependent electronic structure of La1/2Sr3/2MnO4 were investigated by optical conductivity analyses. With decreasing temperature, for E//ab, a broad mi…
Chirality-induced spin texture switching in twisted bilayer graphene
Kunihiro Yananose, Giovanni Cantele, Procolo Lucignano +3
The interlayer van der Waals interaction in twisted bilayer graphene (tBLG) induces both in-plane and out-of-plane atomic displacements showing complex patterns that depend on the…
Doped Valence Bond Solid and Superconductivity on the Shastry-Sutherland Lattice
Bohm-Jung Yang, Yong Baek Kim, Jaejun Yu +1
Motivated by recent experiments on SrCu(BO), we investigate the ground states of the doped Mott insulator on the Shastry-Sutherland lattice. To provide a unified theore…
Electron and orbital correlations in Ca_{2-x}Sr_{x}RuO_{4} probed by optical spectroscopy
J. S. Lee, Y. S. Lee, T. W. Noh +5
The doping and temperature dependent optical conductivity spectra of the quasi-two-dimensional Ca_{2-x}Sr_xRuO_4 (0.0=<x=<2.0) system were investigated. In the Mott insulating stat…
Electronic structures of hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films
W. S. Choi, D. G. Kim, S. S. A. Seo +9
We investigated the electronic structure of multiferroic hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films using both optical spectroscopy and first-principles calculations. Usin…
Oxygen-vacancy-induced charge carrier in n-type interface of LaAlO3 overlayer on SrTiO3 (001): interface vs bulk doping carrier
Yun Li, S. Na Phattalung, S. Limpijumnong +1
We investigated the role of oxygen vacancy in n-type interface of LaAlO3 (LAO) overlayer on SrTiO3 (STO) (001) by carrying out density-functional-theory calculations. Comparing the…
Inevitable high density of oxygen vacancies on the surface of LaAlO3/SrTiO3 heterostructures
Yun Li, Xinyuan Wei, Jaejun Yu
Using density-functional-theory (DFT) calculations with the HSE06 hybrid functional, we accurately evaluate the critical thickness of LaAlO3 film for the intrinsic doping in LaAlO3…
Non-Fermi liquid behavior and scaling of low frequency suppression in optical conductivity spectra of CaRuO
Y. S. Lee, Jaejun Yu, J. S. Lee +4
Optical conductivity spectra of paramagnetic CaRuO are investigated at various temperatures. At T=10 K, it shows a non-Fermi liquid behavior of $Ï_1(Ï)\sim 1/Ï^{\…
Twisted double-layer chiral spin structures in anti-ferromagnetic delafossite PdCrO
Changhwi Park, Jaejun Yu
We predict that the anti-ferromagnetic (AFM) magnetic structure of delafossite PdCrO has a staggered chirality with the double-layer periodicity along the -axis with intrigu…
Anomalous spin susceptibility and magnetic polaron formation in the double exchange systems
Hongsuk Yi, N. H. Hur, Jaejun Yu
The magnetic susceptibility and spin-spin correlation of the double-exchange model for doped manganites are investigated through the Monte Carlo calculations on the three-dimension…
Dynamic Jahn-Teller Mechanism of Superconductivity in MgB
Young-Woo Son, Jaejun Yu, Jisoon Ihm
We propose a novel mechanism of superconductivity in MgB based on the dynamic electronic structure of the -orbitals coupled with phonons. A nonconventional superc…
Suppression of ferromagnetic ordering in doped manganites: Effects of the superexchange interaction
Hongsuk Yi, Jaejun Yu, Sung-Ik Lee
From a Monte Carlo study of the ferromagnetic Kondo lattice model for doped manganites, including the antiferromagnetic superexchange interaction (), we found that the ferr…
Dimensional Crossover driven by Magnetic Ordering in Optical Conductivity of Pr_{1/2}Sr_{1/2}MnO_3
J. H. Jung, E. J. Choi, H. J. Lee +3
We investigated optical properties of Pr_{0.5}Sr_{0.5}MnO_3, which has the A-type antiferromagnetic ordering at a low temperature. We found that T- dependence of spectral weight tr…
Room Temperature Ferroelectric Ferromagnet in 1D Tetrahedral Chain Network
Kyeong Tae Kang, Chang Jae Roh, Jinyoung Lim +17
Ferroelectricity occurs in crystals with broken spatial inversion symmetry. In conventional perovskite oxides, concerted ionic displacements within a three-dimensional network of t…
Orbital-Angular-Momentum Based Origin of Rashba-Type Surface Band Splitting
Seung Ryong Park, Choong H. Kim, Jaejun Yu +2
We propose that existence of local orbital angular momentum (OAM) on the surfaces of high-Z materials play a crucial role in the formation of Rashba-type surface band splitting. Lo…
Polarization screening and induced carrier density at the interface of LaAlO overlayer on SrTiO (001)
Yun Li, Jaejun Yu
We investigate the role of lattice polarization in determination of induced carrier density at the -type interface of LaAlO overlayer on SrTiO (001) by carrying out dens…
Emergence of Orbital Angular Momentum by Inversion Symmetry Breaking and Its Detection by ARPES
Choong H. Kim, Jin-Hong Park, Jun Won Rhim +8
Rashba-split surface band is characterized by a one-to-one correspondence between the electron's momentum k and its spin orientation. Here we show that a similar correspondence bet…
Double polarization hysteresis loop induced by the domain pinning by defect dipoles in HoMnO3 epitaxial thin films
Daesu Lee, Heung-Sik Kim, Seung Yup Jang +5
We report on antiferroelectriclike double polarization hysteresis loops in multiferroic HoMnO3 thin films below the ferroelectric Curie temperature. This intriguing phenomenon is a…
Spin-Orbit Integrated Ground State and Magnetic Anisotropy in SrIrO
Hosub Jin, Hogyun Jeong, Taisuke Ozaki +1
We present a microscopic model for the anisotropic exchange interactions in SrIrO. A direct construction of Wannier functions from first-principles calculations proves…
Spin/Orbital Pattern-Dependent Polaron Absorption in Nd(1-x)Sr(x)MnO3
M. W. Kim, J. H. Jung, K. H. Kim +4
We investigated optical properties of Nd(1-x)Sr(x)MnO3 (x= 0.40, 0.50, 0.55, and 0.65) single crystals. In the spin/orbital disordered state, their conductivity spectra look quite…
Competition between structural distortion and magnetic moment formation in fullerene C
Myung Joon Han, Gunn Kim, Jae Il Lee +1
We investigated the effect of on-site Coulomb interactions on the structural and magnetic ground state of the fullerene C based on density-functional-theory calculations wit…
The effect of lattice distortion and orbital mixing on the optical and magnetic properties of cubic RMnO (R = La, Pr, Nd, Gd, Tb)
M. W. Kim, S. J. Moon, J. H. Jung +4
We investigated the -plane absorption spectra of MnO ( = La, Pr, Nd, Gd, and Tb) thin films. As the -ion size decreases, we observed a drastic suppression of th…
Enhanced Optical Gap in Bi-layered Manganites LaSrMnO near
Myung Whun Kim, H. J. Lee, B. J. Yang +4
We have systematically investigated the optical conductivity spectra of LaSrMnO (). We find that just above the magneti…
Strain Control of Magnetism in Transition-Metal-Atom Decorated Graphene
Bing Huang, Jaejun Yu, Su-Huai Wei
We report a strain-controlled tuning of magnetism in transition-metal-atom-decorated graphene. Our first-principles calculations demonstrate that strain can lead to a sudden change…
A spin-dependent local moment approach to the Anderson impurity model
Choong H. Kim, Jaejun Yu
We present an extension of the local moment approach to the Anderson impurity model with spin-dependent hybridization. By employing the two-self-energy description, as originally p…
Spin cluster operator theory for the Kagome lattice antiferromagnet
Kyusung Hwang, Yong Baek Kim, Jaejun Yu +1
The spin-1/2 quantum antiferromagnet on the Kagome lattice provides a quintessential example in the strongly correlated electron physics where both effects of geometric frustration…
Mott Insulating Ground State and its Proximity to Spin-Orbit Insulators in NaIrO
Hosub Jin, Heungsik Kim, Hogyun Jeong +2
We present an anti-ferromagnetically ordered ground state of NaIrO based on density-functional-theory calculations including both spin-orbit coupling and on-site Coulom…
First-principles study of ultrathin (2 \times 2) Gd nanowires encapsulated in carbon nanotubes
Jae-Hyeon Parq, Jaejun Yu, Gunn Kim
Using density functional calculations, we investigate the structural and magnetic properties of ultrathin Gd and Gd-carbide nanowires (NWs) encapsulated in narrow carbon nanotubes…
Efficient discovery of multiple minimum action pathways using Gaussian process
JaeHwan Shim, Juyong Lee, Jaejun Yu
We present a new efficient transition pathway search method based on the least action principle and the Gaussian process regression method. Most pathway search methods developed so…
Tunable charge donation and spin polarization of metal adsorbates on graphene using applied electric field
Jae-Hyeon Parq, Jaejun Yu, Young-Kyun Kwon +1
Metal atoms on graphene, when ionized, can act as a point charge impurity to probe a charge response of graphene with the Dirac cone band structure. To understand the microscopic p…
Ferroelectricity in artificial bicolor oxide superlattices
Sung Seok A. Seo, Jun Hee Lee, Ho Nyung Lee +7
We report on the growth and properties of high quality bicolor oxide superlattices, composed of two perovskites out of BaTiO3, CaTiO3, and SrTiO3. The artificially grown superlatti…
Magnetic interactions in PdCrO and their effects on its magnetic structure
Manh Duc Le, Seyyoung Jeon, A. I. Kolesnikov +9
We report a neutron scattering study of the metallic triangular lattice antiferromagnet PdCrO. Powder neutron diffraction measurements confirm that the crystalline space group…
Effect of Coulomb Interactions on the Electronic and Magnetic Properties of Two-Dimensional CrSiTe and CrGeTe Materials
Sungmo Kang, Seungjin Kang, Jaejun Yu
We investigate the electronic and magnetic structures of two-dimensional transition metal tri-chalcogenide CrSiTe and CrGeTe materials by carrying out first-principles…
Spin and Orbital Angular Momentum Structures of Cu(111) and Au(111) Surface States
Beomyoung Kim, Choong H. Kim, Panjin Kim +9
We performed angle resolved photoemission (ARPES) studies on Cu(111) and Au(111) surface states with circularly polarized light. Existence of local orbital angular momentum (OAM) i…
Enhanced Upper Critical Fields in a New Quasi-one-dimensional Superconductor Nb2PdxSe5
Seunghyun Khim, Bumsung Lee, Ki-Young Choi +9
We report a discovery of superconductivity with Tc = 5.5 K in Nb2PdxSe5, in which one-dimensional (1D) Nb-Se chains existing along the b-direction hybridize each other to form the…
Modulation of electron carrier density at the n-type LaAlO3/SrTiO3 interface by water adsorption
Yun Li, Jaejun Yu
We investigate energetic stability and dissociation dynamics of water adsorption at the LaAlO3 surface of the n-type LaAlO3/SrTiO3 (LAO/STO) interface and its effect on electronic…
Physical properties of transparent perovskite oxides (Ba,La)SnO3 with high electrical mobility at room temperature
Hyung Joon Kim, Useong Kim, Tai Hoon Kim +9
Transparent electronic materials are increasingly in demand for a variety of optoelectronic applications. BaSnO3 is a semiconducting oxide with a large band gap of more than 3.1 eV…