4원 합금 AlGaAs₂:Mn의 강자성

강병섭,Kang, Byung-Sub 한국재료학회 2020 한국재료학회지 Vol.30 No.12

The electronic structure and magnetic properties of chalcopyrite (CH) AlGaAs2 with dopant Mn at 3.125 and 6.25 % concentrations are investigated using first-principles calculations. The CH AlGaAs2 alloy is a p-type semiconductor with a small band-gap. The AlGaAs2:Mn shows that the ferromagnetic (FM) state is the most energetically favorable one. The Mn-doped AlGaAs2 exhibits FM and strong half-metallic ground states.The spin polarized Al(Ga,Mn)As2 state (Al-rich system) is more stable than the (Al,Mn)GaAs2 state (Ga-rich system), which has a magnetic moment of 3.82mB/Mn. The interaction between Mn-3d and As-4p states at the Fermi level dominates the other states.The states at the Fermi level are mainlyAs-4p electrons, which mediate strong interaction between the Mn-3d and As-4p states. It is noticeable that the FM ordering of dopant Mn with high magnetic moment originates from the As(4p)-Mn(3d)-As(4p) hybridization, which is attributed to the partially unfilled As-4pbands. The high FM moment of Mn is due to the double-exchange mechanism mediated by valence-band holes.

GaAs 및 AlN 와 Cr 합금의 반금속 특성

강병섭,채광표,강희재 한국물리학회 2006 새물리 Vol.53 No.5

The electronic and the magnetic properties of zinc-blende CrAs(001), (Ga,Cr)As, and (Al,Cr)N are determined by using the first-principles full-potential linear muffin-tin orbital method. The local magnetic moments of Cr are about 2.3$\mu_{B}$ and 2.9$\mu_{B}$ for (Al,Cr)N and (Ga,Cr)As, respectively. The (Ga$_{1-x}$Cr$_{x}$)As and zinc-blende CrAs(001) show half-metallic characters. The wurtzite (Al,Cr)N, shows a half-metallic behavior for low concentrations of Cr. The gap of energy gap in the wurtzite (Al,Cr)N is noted to decrease with increasing Cr concentration. (Ga,Cr)As, (Al,Cr)N, (Al,Cr)As, 그리고 CrAs(001) 계에 대한 전자적 성질 및 자성을 full-potential linear muffin-tin orbital (FP-LMTO) 방법을 사용하여 연구하였다. AlN 와 GaAs 내의 Cr 의 자기모멘트는 각각 2.3$\mu_{B}$ 와 2.9$\mu_{B}$ 인데 AlAs 내 Cr 의 경우는 이와 차이를 보인다. Cr 의 농도에 따라 자기모멘트는 달라지고 살창상수 변화에 대해 매우 민감한 특성을 보인다. Wurtzite (Al$_{1-x}$Cr$_{x}$)N, zinc-blende (Al$_{1-x}$Cr$_{x}$)As 및 (Ga$_{1-x}$Cr$_{x}$)As 는 반금속 특성은 나타내지만 Cr 농도에 따라 그 특성은 약간 달랐다. 또한, Cr 농도의 증가에 대한 (Al,Cr)N 계의 에너지 띠 간격의 변화를 조사하였다.

III-V 족 질화물계와 불순물 Cr의 반금속 특성

강병섭,채광표 한국물리학회 2007 새물리 Vol.55 No.6

The electronic and the magnetic properties for zinc-blende and wurtzite AlN, GaN, and InN structures with Cr concentrations from 0.027 to 0.166 were investigated by using the full potential linear muffin-tin orbital method. The energy gap in Cr-doped wurtzite AlN or InN decreases with increasing concentration. For (Al,Cr)N, the half-metallic behavior disappeared at a concentration of 0.166; however, (In,Cr)N, shows a half-metallic character at this concentration. Our calculated result is in agreement with the results of other previous works. 제일 원리적인 full-potential linear muffin-tin orbital (FPLMTO) 방법을 사용하여 zinc-blende 및 wurtzite AlN, GaN, 그리고 InN 내에 Cr 의 농도를 0.027에서 0.166 까지 변화하면서 전자적 구조 및 자기적 성질을 연구하였다. Wurtzite (Al,Cr)N 및 (In,Cr)N 계의 밴드 간격과 반금속 에너지 간격은 농도가 0.027 에서 0.166 까지 증가할 때 모두 감소한다. (Al,Cr)N의 경우 반금속특성은 Cr 농도가 0.166의 농도에서 사라진다. 그러나, (In,Cr)N 의 경우 이 농도에서 반금속 성질이 유지된다. 이러한 결과와 계산에 사용된 평형상태의 원자구조 등을 다른 이론 및 실험 결과와 비교하였다.

Ferromagnetic-paramagnetic Transition in Cu-doped GaN

강병섭,김경섭,강희재,유성초 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.61

The electronic properties for Cu-doped GaN at several concentrations are examined using a firstprinciples full-potential linear muffin-tin orbital method. Ga0.9375Cu0.0625N, a global magnetic moment of 2.0µB per supercell, with a localized magnetic moment of 0.67µB per Cu atom is found. For Ga0.875Cu0.125N, the magnetism of the supercell disappears due to an interaction of neighboring Cu atoms, and a phase transition from ferromagnetic to paramagnetic states occurs. We note that the range of concentrations for spin-polarization may be restricted within very narrow limits.

Cu 금속 내부의 3d 전이금속 불순물

李元植,李才熙,姜昞燮 慶一大學校 1999 論文集 Vol.16 No.5

We report the electronic and the magnetic properites and the interaction energies of impurity-impurity pairs of 3d transition-metals from vanadium to nickel in a copper. First-principles, self-consistent electronic structure calculations utilizing the tight-binding linear muffin-tin orbitals scheme were performed for Cu?M and Cu?M₂embedded clusters, where M stands for V, Cr, Mn, Fe, Co, or Ni. The pair interaction for the Co and Ni impurities is a weak repulsion while cimers of V, Cr, Mn, and Fe in Cu indicate an attractive interaction. The weakly repulsive interaction for Co and Ni is due to the breakup of two strong 3d impurity-3d host bonds.

V/Cu 와 Cu/V/Cu 의 전자적 구조 및 자성

강병섭,송영열 한국물리학회 2006 새물리 Vol.53 No.5

The electronic and the magnetic properties of thin V/Cu films and Cu/V/Cu sandwiches were determined by using the first-principles full-potential linear muffin-tin orbital method. Magnetic ordering does not exist in the 1-ML (monolayer) V on the Cu(100) and the Cu(111) surfaces, in contrast to the magnetism for thin V/Ag or V/Fe films. Even though the spin polarization in the sandwich with 1-3 ML's of V with an interfacial orientation of (111) was very weak, magnetic properties are not found because the energy of magnetic splitting was very low. Our results for thin films with 1-3 ML's of V provide no evidence for either in-plane or out-of-plane long-range magnetic ordering. The results for the thin V/Cu(100) film are compared with other theoretical results and with the data obtained by using angle-resolved ultraviolet photoemission spectroscopy (ARUPS). 제일 원리적인 full-potential linear muffin-tin orbital (FP-LMTO) 방법을 사용하여 V/Cu 합금계의 계면 및 표면의 전자적 구조와 자성연구를 하였다. V/Ag 및 V/Fe 초 박막계의 자성과는 다르게, Cu 금속 위 1-monolayer (1-ML)의 vanadium은 (100) 및 (111) 성장면에서 자기적 성질이 없었다. Cu/V(111)/Cu 구조계에서 1-ML vanadium은 매우 약하게 스핀편극은 (반강자성) 유발되지만 자기분리 에너지가 매우 낮아서 안정된 자기적 성질은 나타나지 않았다. 박막의 성장면내에서나 (in-plane) 성장면에 수직한 방향에서나 (out-of-plane) vanadium 은 긴거리 자기적 질서의 존재는 어렵다는 결과를 얻었다. 이러한 V/Cu(100) 의 전자적 상태에 대한 결과를 angle-resolved ultraviolet photoemission spectroscopy (ARUPS) 실험결과 및 다른 이론결과와 비교하였다.

AlGaP₂ 반도체내와 표면의 Mn에 대한 제일원리 해석

강병섭,Kang, Byung Sub 한국반도체디스플레이기술학회 2021 반도체디스플레이기술학회지 Vol.20 No.1

The electronic and magnetic properties for Mn-adsorbed on the chalcopyrite (CH) AlGaP2 semiconductor are investigated by using first-principles FPLMTO method. The clean CH-AlGaP2 without adsorbed Mn is a p-type semiconductor with a direct band-gap. The Mn-adsorbed CH-AlGaP2 exhibits the ferromagnetic state. It is more energetically stable than the other magnetic ones. The interstitial site on P-terminated surface is more energetically favorable one than the Al/Ga-terminated surface, or the other adsorbing sites. In the case of Mn-adsorbed Al/Ga-terminated surface, it is induced a strong coupling between Mn-3d and neighboring P-3p electrons. The holes of partially unoccupied minority Mn-3d state and majority (or minority) Al-3p or P-3p state are induced. Thus a high magnetic moment of Mn is sustained by holes-mediated double-exchange coupling. It is noticeable that the semiconducting and half-metallic characteristics of CH-AlGaP2:Mn thin film is disappeared.

AlN 반도체와 Cu의 도핑 농도에 대한 자성

강병섭,이행기,Kang, Byung-Sub,Lee, Haeng-Ki 한국반도체디스플레이기술학회 2010 반도체디스플레이기술학회지 Vol.9 No.3

First-principles calculations based on spin density functional theory are performed to study the spin-resolved electronic properties of AlN doped with a Cu concentration of 6.25%-18.75%. The ferromagnetic state is more energetically favorable state than the antiferromagnetic state or the nonmagnetic state. For $Al_{0.9375}Cu_{0.0625}N$, a global magnetic moment of 1.26 mB per supercell, with a localized magnetic moment of 0.75 $m_B$ per Cu atom is found. The magnetic moment is reduced due to an increase in the number of Cu atoms occupying adjacent cation lattice position. For $Al_{0.8125}Cu_{0.1875}N$, the magnetism of the supercell disappears by the interaction of the neighboring Cu atoms. The nonmagnetic to ferromagnetic phase transition is found to occur at this Cu concentration. The range of concentrations that are spin-polarized should be restricted within very narrow.

Palladium 금속표면 및 Bulk에서의 Hydrogen interactions

강병섭 慶北大學校 基礎科學硏究所 1993 慶北大學敎 基礎科學硏究所 硏究論文集 Vol.14 No.-

Palladium 금속에서 수소의 흡착 및 확산현상

강병섭 慶北大學校 基礎科學硏究所 1993 慶北大學敎 基礎科學硏究所 硏究論文集 Vol.14 No.-