visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2022-05-13 14:30 
일시 May. 13 (Fri.), 02:30 PM 
장소 Zoom webinar 
연사 Dr. Kun-Rok Jeon(Department of Physics, Chung-Ang University) 

SRC Seminar

 

 

Topological Superconducting Spintronics Towards Zero-Power Computing Technologies

 

Dr. Kun-Rok Jeon

Department of Physics, Chung-Ang University

 

May. 13 (Fri.), 02:30 PM

https://kaist.zoom.us/j/88323922428
회의 ID: 883 2392 2428

암호: 839974

Abstract:

Semiconductor (SC) spintronics [1-4] aims to integrate memory and logic functions into a single device. Ferromagnetic tunnel contacts have emerged as a robust and technically viable method to inject spin current into a SC up to room temperature, and to detect it [3-7]. Intriguingly, it has been established that the spin current in ferromagnetic tunnel contacts can be created by thermal means (driven by a heat flow), namely Seebeck spin tunneling [8]. So far, the creation of thermal spin current relies on the spin-dependent energy dispersion of electronic states around the Fermi energy (EF), which determines thermoelectric properties. In the first part of my talk, I will describe a conceptually new approach to tailor the thermal spin current in ferromagnetic tunnel contacts to SCs exploiting spin-dependent thermoelectric properties away from EF through the application of a bias voltage across the tunnel contact [9,10].

Combining superconductivity with spintronics brings in a variety of notable phenomena which do not exist in the normal state, for instance quantum coherence, superconducting exchange coupling and spin-polarized triplet supercurrents [11,12]. This nascent field of superconducting spintronics promises to realize zero-energy-dissipation spin transfer and magnetization switching. Recent equilibrium (zero-bias) studies of the Josephson effect in S/FM/S (FM: ferromagnet; S: Superconductor) junctions and the critical temperature Tc modulation in FM/S/FM and S/FM/FM' superconducting spin valves have demonstrated that engineered magnetically-inhomogeneous S/FM interfaces can generate long-range triplet pairing states which explicitly carry spin [11,12]. However, direct measurement of triplet spin transport through a singlet S has not so far been achieved. In the second part, I will describe an essentially different approach, namely, a time-dependent ferromagnetic magnetization [ferromagnetic resonance (FMR)] can drive spin-polarized transport in a singlet S via spin-triplet states induced by spin-orbit coupling [13,14].

If time permits, I will briefly outline outstanding technical issues for the realization of energy-efficient (or even dissipation-less) spintronic technologies and present my research direction of how to address these issues via topology physics [15,16].

Reference: [1] Rev. Mod. Phys. 80, 1517 (2008), [2] Rev. Mod. Phys. 76, 323 (2004), [3] Nat. Mater. 11, 400 (2012), [4] Semicond. Sci. Technol. 27, 083001 (2012), [5] Nature 462, 491 (2009), [6] Appl. Phys. Express 4, 023003 (2011), [7] Phys. Rev. Appl. 2, 034005 (2014), [8] Nature 475, 82 (2011), [9] Nat. Mater. 13, 360 (2014), [10] Phys. Rev. B 91, 155305 (2015), [11] Nat. Phys. 11, 307 (2015), [12] Rep. Prog. Phys. 78, 104501 (2015), [13] Nat. Mater. 17, 499 (2018), [14] Phys. Rev. X 10, 031020 (2020), [15] Nat. Mater. 20, 1358 (2021), [16] Under review in Nat. Nanotech. (2022).

 

Contact: SunYoung Choi, (sun.0@kaist.ac.kr)

Center for Quantum Coherence in Condensed Matter, KAIST

번호 날짜 장소 제목
188 2018-10-18 16:00  #1323, E6-2  Applications of nonlinear optics for condensed matter researches file
187 2018-10-18 10:00  #1323, E6-2  Understanding membrane protein folding using single-molecule force techniques file
186 2018-10-16 10:00  #1323, E6-2  Capturing protein cluster dynamics and gene expression output in live cells file
185 2018-10-15 16:00  #1323, E6-2  Universal properties of macroscopic current-carrying systems file
184 2018-10-12 16:00  E6-2. 1st fl. #1323  Direct observation of a two-dimensional hole gas at oxide interfaces file
183 2018-10-12 14:30  E6-2. 1st fl. #1323  Quantum Advantage in Learning Parity with Noise file
182 2018-10-11 16:00  #1323, E6-2  Dirac electrons in a graphene quasicrystal file
181 2018-10-04 16:00  #1323, E6-2  Engineering light absorption in an ultrathin semiconductor metafilm file
180 2018-09-20 16:00  #1323, E6-2  Toward Cancer Treatment Using Terahertz Radiation: Demethylation of Cancer DNA file
179 2018-09-07 15:00  학술문화관 (E9), 2층 양승택 오디토리움  Recent developments in density functional theory: From new functionals to the nature of the chemical bond file
178 2018-09-05 16:00  #1323, E6-2  Shining a light on fractional excitations file
177 2018-09-04 14:30  E6-2. 2st fl. #2502  Ultrafast time- and angle-resolved photoemission spectroscopy (tr-ARPES) with extreme ultraviolet laser pulses file
176 2018-08-01 11:00  양분순 빌딩 (E16-1) 207호  Future of AI: Is the brain a computer? file
175 2018-07-27 15:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6).  Muon g-2 in the 2HDM and MSSM: comprehensive numerical analysis and absolute maxima file
174 2018-07-27 13:30  #1323, E6-2  Magnetic reversal of artificial spin ice file
173 2018-07-26 14:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6).  Inflation in String Theory and Backreaction file
172 2018-07-13 14:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6).  Loop Induced Single Top Partner Production and Decay at the LHC
171 2018-07-12 17:00  Room 5318, KAIST Natural Sciences Lecture Hall(E6)  The MilliQan Experiment: Search for Milli-Charged Particles at the LHC
170 2018-07-09 14:00  #1323, E6-2  The principles of collective learning file
169 2018-07-02 15:00  Seminar Room (C303), Creation Hall (3F), KAIST Munji Campus  High Precision Magnetic Field Measurement for the Muon g-2 Experiment file