▪ 연구실 소개 : STM분석연구실 (전상준 교수님)
· 홈페이지: Goolge Scholar​

· 구성원

▪ 연구방법 

Our focus is on the exploration of topological materials and 2D materials using scanning tunneling microscopy (STM). 

Topological materials:

Solid state materials have been newly classified based on topology in their electronic band structure, resulting in a group known as topological materials. These materials include topological insulators (TI), topological Dirac and Weyl semimetals (DSM, WSM), and topological superconductors, and are characterized by symmetry-protected bound states that are robust against small perturbations and disorder. These properties make topological materials potentially useful for electronics, spintronics, and quantum computing. Ongoing research in this field includes investigations into electron transport without scattering in TI, chiral anomalies in WSM, and Majorana zero modes (MZM) in topological superconductors. Additionally, electron correlation effects in topological materials have recently gained significant attention.

2D materials:

2D materials are characterized by their extremely thin thickness, typically only a few atoms, which sets them apart from conventional materials with a bulk structure in three dimensions. This unique dimensionality gives rise to distinctive physical and electronic properties in 2D materials. Graphene is one of the most well-known 2D materials, consisting of a single layer of carbon atoms arranged in a honeycomb lattice. Interestingly, the electronic properties of graphene can be significantly altered by the way individual layers are stacked. For example, magic-angle twisted bilayer graphene (MATBG) exhibits unconventional superconductivity and strong electron correlation, unlike single-layer graphene. Transition metal dichalcogenides (TMDs), other groups of 2D materials, consist of a layer of transition metal atoms sandwiched between two layers of chalcogen atoms. These materials display various intriguing electronic and optical properties, including a tunable bandgap that varies based on the number of layers.​ 

​▪ ​연구장비

-Homebuilt 4K UHV STM equipped with glove box and micro-positioner

-UNISOKU 4K UHV STM equipped with 6T superconducting magnet

-Helium liquefier (22 liters of LHe / day) and He recovery system

-Homebuilt “Align and Stack” stage for 2D materials

-General purpose atomic force microscope (AFM)​ 

▪ 최근 연구 주제/성과/수행과제

Topological materials:

-Symmetry dictated grain boundary state in a two-dimensional topological insulator, Nano Letters, 20, 8 (2020) https://doi.org/10.1021/acs.nanolett.0c01756

-Observation of a Majorana zero mode in a topologically protected edge channel, Science, 364, 1255-1259 (2019) https://doi.org/10.1126/science.aax1444

-Higher-Order Topology in Bismuth, Nature Physics 14, 918-924 (2018) https://doi.org/10.1038/s41567-018-0224-7

-Distinguishing a Majorana zero mode using spin resolved measurements, Science, 358, 772-776 (2017) https://doi.org/10.1126/science.aan3670

-High-resolution studies of the Majorana atomic chain platform, Nature Physics 13, 286, (2016) https://doi.org/10.1038/nphys3947

-Landau quantization and quasiparticle interference in the three-dimensional Dirac semimetal Cd3As2, Nature Materials 13, 851-856 (2014) https://doi.org/10.1038/nmat4023

-One-dimensional topological edge states of bismuth bilayers, Nature Physics 10, 664-669 (2014) https://doi.org/10.1038/nphys3048

-Observation of Majorana fermions in ferromagnetic atomic chains on a superconductor, Science 346, 602-607 (2014) https://doi.org/10.1126/science.1259327

2D materials:

-Direct observation of multiband charge density waves in NbTe2, Physical Review B, 106, 125110 (2022) https://doi.org/10.1103/PhysRevB.106.125110

-Reshaped Weyl fermionic dispersions driven by Coulomb interactions in MoTe2, Physical Review B, 105, 045143 (2022) https://doi.org/10.1103/PhysRevB.105.045143

-Cascade of electronic transitions in magic-angle twisted bilayer graphene, Nature, 582, 7811 (2020) https://doi.org/10.1038/s41586-020-2339-0

STM Instrumentation

-A modular ultra-high vacuum millikelvin scanning tunneling microscope, Review of Scientific Instruments, 91, 023703 (2020) https://doi.org/10.1063/1.5132872