Publications

Preprint

 

qmsu_pub50

Emergent topological magnetism in Hund's excitonic insulator

R. Okuma, K. Yamagami, Y. Fujisawa, C. H. Hsu, Y. Obata, N. Tomoda, M. Dronova, K. Kuroda, H. Ishikawa, K. Kawaguchi, K. Aido, K. Kindo, Y. H. Chan, H. Lin, Y. Ihara, T. Kondo, Y. Okada

arXiv:2405.16781

 

qmsu_pub49

Imaging emergent exotic quasiparticle state in a frustrated transition metal oxide

Y. Fujisawa, A. Krishnadas, C. H. Hsu, T. Takeda, S. Liu, M. P. Almanza, Y. Obata, D. van Dinter,
K. Yamagami, G. Chang, M. Kobayashi, C. Y. Kuo, Y. Okada

arXiv:2306.06708

 

qmsu_pub48

Visualizing magnetic field-induced rotational electronic symmetry breaking in a spinel oxide superconductor

Y. Fujisawa, A. Krishnadas, C. H. Hsu, B. Smith, M. P. Almanza, Y. Obata, D. van Dinter, G. Chang,
 Y. Nagai, T. Machida, Y. Okada

arXiv:2306.06711  

 

Publication 

 

qmsu_pub47

Imaging Josephson Vortices on Curved Junctions

Y. Fujisawa, A. Krishnadas, B. Smith, M. Pardo-Almanza, H. Hiyane, Y. Nagai, T. Machida, Y. Okada

Phys. Rev. B 110, 224501 (2024) 

 

qmsu_pub46

Revealing Pronounced Electron-Hole Fermi Pockets in the Charge Density Wave Semimetal LaTe3

T. Nakamura, Y. Fujisawa, B. R. M. Smith, N. Tomoda, T. J. Hasiweder, Y. Okada

Phys. Rev. B 110 235415 (2024)  

 

qmsu_pub45

Uncovering hidden Fermi surface instabilities through visualizing unconventional quasi-particle interference in CeTe3

B. R. M. Smith, Y. Fujisawa, P. Wu, T. Nakamura, N. Tomoda, S. Kuniyoshi, D. Ueta, R. Kobayashi, R. Okuma, K. Arai, K. Kuroda,
C-H. Hsu, G. Chang, C-Y. Huang, H. Lin, Z. Y. Wang, T. Kondo, Y. Okada

Phys. Rev. Mat. 8 104004 (2024)

 

qsmu_pub44

Dimensionality-driven power-law gap in the bilayer TaTe2 grown by molecular-beam epitaxy

Bruno. Kenichi Saika,S. Yoshida,M. P. Almanza, N. Mitsuishi, M. Sakano, Y. Fujisawa, Y. Wang, Y. Iwasa, H. Matsuoka, H. Takahashi,S. Ishiwata, Y. Okada, M. Nakano and K. Ishizaka

APL Materials 12, 071105 (2024) [Featured]

 

qmsu_pub43

Nontrivial Topology in Monolayer MA2Z4 (M = Ti, Zr, or Hf; A = Si or Ge; and Z = N, P, As, Sb, or Bi)

Ina Marie R. Verzola, R. A. B. Villaos, Z. Q. Huang, C. H. Hsu, Y. Okada, H. Lin, and F. C. Chuang

J. Phys. Chem. C 128, 6829–6835 (2024)

 

qmsu_pub42

Magnetotransport properties in van-der-Waals RTe3 (R = La, Ce, Tb)

T. Higashihara, R. Asama, R. Nakamura, M. Watanabe, N. Tomoda,
T. J. Hasiweder, Y. Fujisawa, Y. Okada, T. Iwasaki, K. Watanabe, T. Taniguchi, N. Jiang, and Y. Niimi

[Editor's Suggestion]

Physical Rev. B 109, 134404 (2024)

 

qmsu_pub41

Widely tunable Berry curvature in the Magnetic Semimetal Cr1+dTe2

Y. Fujisawa, M. Pardo-Almanza, C. H. Hsu, A. Mohamed, K. Yamagami, A. Krishnadas, F. C. Chuang, K. H. Khoo, J. Zang, A. Soumyanarayanan, Y. Okada

Adv. Mater. 2207121(2023)

 

qmsu_pub40

Enhancement of spin–flop-induced magnetic hysteresis in van der Waals magnet (Fe1-xCox)5GeTe2

T Ohta, K. Kurokawa, N. Jiang, K. Yamagami, Y. Okada, and Y. Niimi

Appl. Phys. Lett. 122, 152402 (2023)

 

qmsu_pub39

Visualization of robust two-dimensional bulk states with suppressed surface state on epitaxial PdCoO2 thin films with bipolar surfaces

T. Kawamoto, A. Krishnadas, C. H. Hsu, M. Pardo-Almanza,
Y. Fujisawa, G. Chang, T. Harada, Y. Okada

Phys. Rev. Materials 7, 024001 (2023)

 

qmsu_pub38

Controlling inversion disorder in a stoichiometric spinel magnet

Margarita G. Dronova, Feng Ye, Scott E. Cooper, Anjana Krishnadas, Christina M. Hoffmann, Yuita Fujisawa,
Yoshinori Okada, Daniel I. Khomskii, Yejun Feng

PNAS 119, e2208748119 (2022)

 

qsmu_pub37

Large antiferromagnetic fluctuation enhancement of the thermopower at a critical doping in magnetic semimetal Cr1+dTe2

M. Atwa, Y. Fujisawa, T. Onishi, M. Pardo-Almanza, M. Couillard, K. Harada, T. Takeuch, Y. Okada

Phys. Rev. B 106, 155112 (2022)

 

qmsu_pub36

Anomalous Magnetic Moment Direction under Magnetic Anisotropy Originated from Crystalline Electric Field
in van der Waals Compounds CeTe3 and CeTe2Se

D. Ueta, R. Kobayashi, H. Sawada, Y. Iwata, S. Yano, S. Kuniyoshi, Y. Fujisawa, T. Masuda, Y. Okada, and S. Itoh

J. Phys. Soc. Jpn. 91, 094706 (2022)

 

qsmu_pub35

Metallic delafossite thin films for unique device applications

T. Harada and Y. Okada

APL Materials 10, 070902 (2022)  [FEATURED]

 

qsmu_pub34

Enhanced d–p hybridization intertwined with anomalous ground state formation in van der Waals-coupled magnetic metal Fe5GeTe2

K. Yamagami, Y. Fujisawa, M. Pardo-Almanza, B. R. M. Smith, K. Sumida, Y. Takeda, and Y. Okada

Phys. Rev. B 106, 045137 (2022)

 

qsmu_pub33

Observation of near EF Fermi-arc van Hove singularity with prominent coupling to phonon in a van der Waals coupled Weyl semimetal

Z. Wang, C. Y. Huang, C. H. Hsu, H. Namiki, T. R. Chang, F. C. Chuang, H. Lin, T. Sasagawa, V. Madhavan, and Y. Okada

Phys. Rev. B 105, 075110 (2022)

 

qsmu_pub32

Magnetic frustration in a van der Waals metal CeSiI

R. Okuma, C. Ritter, G. J. Nilsen, Y. Okada

Phys. Rev. Materials (L) 5, L121401 (2021)

 

qsmu_pub31

Visualizing superconductivity in an inversion-symmetry- broken doped Weyl semimetal

Z. Wang, J. Olivares, H. Namiki, V. Pareek, K. Dani, T. Sasagawa, V. Madhavan and Y. Okada

Phys. Rev. B 104, 115102 (2021)

 

qsmu_pub30

Itinerant ferromagnetism mediated by giant spin polarization of metallic ligand band in van der Waals magnet Fe5GeTe2

K. Yamagami, Y. Fujisawa, B. Driesen, C. H. Hsu, K. Kawaguchi, H. Tanaka, T. Kondo, Y. Zhang, H. Wadati, K. Araki, T. Takeda, Y. Takeda, T. Muro, F. C. Chuang, Y. Niimi, K. Kuroda, M. Kobayashi, Y. Okada

 Phys. Rev. B (L) 103, L060403 (2021)

 

qsmu_pub29

Single Molecular Adsorption of Terbium(III) Bis-phthalocyaninato (TbPc2) Governed by Two Surface Reconstructions of Perovskite Type SrVO3 Epitaxial Ultrathin Film

Hirofumi Oka, Keiichi Katoh, Yoshinori Okada, Daichi Oka, Taro Hitosugi, Masahiro Yamashita, and Tomoteru Fukumura

Chem. Lett., 50, 1489 (2021)

 

Butterfly-shaped magnetoresistance in van der Waals ferromagnet Fe5GeTe2

T. Ohta, M. Tokuda, S. Iwakiri, K. Sakai, B. Driesen, Y. Okada, K. Kobayashi, and Y. Niimi

AIP Advances 11, 025014 (2021)

Shubnikov-de-Haas oscillation and possible modification of effective mass in CeTe3 thin films

M. Watanabe, R. Nakamura, S. Lee, T. Asano, T. Ibe, M. Tokuda, H. Taniguchi, D. Ueta, Y. Okada, K. Kobayashi, and Y. Niimi

AIP Advances 11, 015005 (2021)

 

qsmu_pub28

Tailoring Magnetism in Self-intercalated Cr1+δTe2 Epitaxial Films

Y. Fujisawa, M. Pardo-Almanza, J. Garland, K. Yamagami, X. Zhu, X. Chen, K. Araki, T. Takeda, M. Kobayashi, Y. Takeda, C. H. Hsu, F. C. Chuang, R. Laskowski, K. H. Khoo, A. Soumyanarayanan, and Y. Okada

Phys. Rev. Materialls 4, 114001 (2020)

 

qsmu_pub27

Fermionic Order by Disorder in a van der Waals Antiferromagnet

R. Okuma, D. Ueta, S. Kuniyoshi, Y. Fujisawa, B. Smith, C. H. Hsu, Y. Inagaki, W. Si, T. Kawae, H. Lin, F. C. Chuang, T. Masuda, R. Kobayashi, Y. Okada

Scientific Reports 10, 15311 (2020)

 

qmsu_pub26

Quantum oscillations with magnetic hysteresis observed in CeTe3 thin films

M. Watanabe, S. Lee, T. Asano, T. Ibe, M. Tokuda, H. Taniguchi, D. Ueta, Y. Okada, K. Kobayashi, and Y. Niimi

Appl. Phys. Lett. 117, 072403 (2020)

 

qsmu_pub25

Enhancement of coercive field in atomically-thin quenched Fe5GeTe2

T. Ohta, K. Sakai, H. Taniguchi, B. Driesen, Y. Okada, K. Kobayashi and Y. Niimi

Appl. Phys. Express 13, 043005 (2020)

 

qsmu_pub24

Three-dimensional electronic structure in ferromagnetic Fe3Sn2 with breathing kagome bilayers

H. Tanaka, Y. Fujisawa, K. Kuroda, R. Noguchi, S. Sakuragi, C. Bareille, B. Smith, C. Cacho, S. W. Jung, T. Muro, Y. Okada, and T. Kondo

Phys. Rev. B 101, 161114(R) (2020)

 

qsmu_pub23

Top-down Approach using Supercritical Carbon Dioxide Ball Milling for Producing Sub-10 nm scaled Bi2Te3 Powders

M. Atwa, T. Nakagawa, A. Yonamine, D. C. Lloyd, M. Schreiber, K. Miyazaki, T. Takeuchi and Y. Okada

Applied Physics Express 13 067002 (2020)

 

qsmu_pub22

Width-induced metal-insulator transition in SrVO3 lateral nanowires spontaneously formed on the ultrathin film

H. Oka, Y. Okada, K. Kaminaga, D. Oka, T. Hitosugi, and T. Fukumura

Applied Physics Letters 117, 051603(2020)

 

qsmu_pub21

Two distinct surface terminations of SrVO3 (001) ultrathin films as an influential factor on metallicity

H. Oka, Y. Okada, T. Hitosugi, and T. Fukumura

Appl. Phys. Lett. 113, 171601 (2018)

 

qsmu_pub20

Disorder induced power-law gaps in an Insulator-Metal Mott transition

Z. Wang, Y. Okada, J. O’ Neal, W. Zhou, D. Walkup, C. Dhital, T. Hogan, P. Clancy, Y. J. Kim, Y. F. Hu, L. Santos, S. D. Wilson, N, Trivedi and V. Madhavan

PNAS 115, 11198 (2018)

 

qsmu_pub19

Anisotropic Band Splitting in Monolayer NbSe2: Implications for Superconductivity and Charge Density Wave

Y. Nakata, K. Sugawara, S. Ichinokura, Y. Okada, T. Hitosugi, T. Koretsune, K. Ueno, S. Hasegawa, T. Takahashi, and T. Sato,

npj 2D Materials and Applicationsvolume 2, 12 (2018)

 

qsmu_pub18

Atomic-scale visualization of oxide thin-film surfaces

K. Iwaya, T. Ohsawa, R. Shimizu, Y. Okada, and T. Hitosugi

Sci Technol Adv Mater. 19(1): 282–290 (2018).

 

qsmu_pub17

Scanning tunneling spectroscopy of superconductivity on surfaces of LiTi2O4(111) thin films

Y. Okada, Y. Ando, R. Shimizu, E. Minamitani, S. Shiraki, S. Watanabe, and T. Hitosugi

Nature Communications 8, 15975 (2017)

 

qsmu_pub16

Quasiparticle interference on cubic perovskite oxide surfaces

Y. Okada, T. R. Chang, G. Chang, R. Shimizu, H. T. Jeng, S. Shiraki, A. Bansil, H. Lin, T. Hitosugi

Phys. Rev. Lett. 119, 086801 (2017)

 

qsmu_pub15

Monolayer 1T-NbSe2 as a Mott insulator

Y. Nakata, K. Sugawara, R. Shimizu, Y. Okada, P. Han, T. Hitosugi, K. Ueno, T. Sato, and T. Takahashi

NPG Asia Materials 8, e321 (2016)

 

qsmu_pub14

Nanoscale determination of the mass enhancement factor in the lightly doped bulk insulator ​lead selenide

I. Zeljkovic, K. L. Scipioni, D. Walkup, Y. Okada, Wenwen Zhou, R. Sankar, G. Chang,Y. J. Wang, H. Lin, A. Bansil, F. Chou, Z. Wang and V. Madhavan

Nature Communication 6, 6559-6563 (2015)

 

qsmu_pub13

Dirac mass generation from crystal symmetry breaking on the surfaces of topological crystalline insulators

I. Zeljkovic★, Y. Okada★, C. Y. Huang, R. Sankar, D. Walkup, W. Zhou, M. Serbyn, F. Chou, W. F. Tsai, H. Lin, A. Bansil, L. Fu, M. Z. Hasan, V. Madhavan

Nature Materials 14, 318–324 (2015)

 

qsmu_pub12

Mapping the unconventional orbital texture in topological crystalline insulators

I. Zeljkovic★, Y. Okada★, C. Y. Huang, R. Sankar, D. Walkup, W. Zhou, M. Serbyn, F. Chou, W. F. Tsai, H. Lin, A. Bansil, L. Fu, M. Z. Hasan, V. Madhavan

Nature Physics 10, 572-577 (2014)

 

qsmu_pub11

Electronic phase separation in the doped spin-orbit driven Mott phase of Sr3(Ir1-xRux)2O7

C. Dhital, T. Hogan, W. Zhou, X. Chen, Z. Ren, M. Pokharel, Y. Okada, M. Heine, W Tian, Z. Yamani, C. Opeil, J. S. Helton, J. W. Lynn, Z. Wang, V. Madhavan, S. D. Wilson

Nature Communications 5, 3377 (2014)

 

qsmu_pub10

Observation of Dirac node formation and mass acquisition in a topological crystalline insulator

Y. Okada, M. Serbyn, H. Lin, D. Walkup, W. Zhou, C. Dhital, M. Neupane, S. Xu, Y. J. Wang, R. Sankar, F. Chou, A. Bansil, Z. Hasan, S. D. Wilson, L. Fu and Vidya Madhavan

Science 341, 1496-1499 (2013)

 

qsmu_pub9

Topological insulators: Plasmons at the surface

Yoshinori Okada, Vidya Madhavan

Nature Nanotechnologies 8, 541-542 (2013)

 

qsmu_pub8

Topological dangling bonds with large spin splitting on the surfaces of Bi2Se3

Hsin Lin, T. Das, Y. Okada, M. C. Boyer, W. D. Wise, M. Tomasik, B. Zhen, E. Hudson, W. Zhou, V. Madhavan, C. Y. Ren, H. Ikuta, and A. Bansil1

Nano Letters, 13, 1915–1919 (2013)

 

qsmu_pub7

Imaging the evolution of metallic states in a spin-orbit interaction driven correlated iridate

Y. Okada, D. Walkup, H. Lin, C. Dhital, T. R. Chang, S. Khadka, W. Zhou, H. T. Jeng, A. Bansil, Z. Wang, S. Wilson, V. Madhavan

Nature Materials 12, 707-713 (2013)

 

qsmu_pub6

Ripple modulated electronic structure of a 3D topological insulator

Y. Okada, W. Zhou, D. Walkup, C. Dhital, S. D. Wilson, V. Madhavan

Nature Communications 3, 1158 (6 pages) (2012)

 

qsmu_pub5

Visualizing Landau levels of Dirac electrons in a one dimensional potential

Y. Okada, Wenwen Zhou, Chetan. Dhital, D. Walkup, Ying Ran, Z. Wang, Stephen D. Wilson, V. Madhavan

Phys. Rev. Lett. 109, 166407 (2012)

 

qsmu_pub4

Direct Observation of Broken Time-Reversal Symmetry on the Surface of a Magnetically Doped Topological Insulator

Y. Okada, C. Dhital, W. Zhou, E. D. Huemiller, H. Lin, S. Basak, A. Bansil, Y. -B. Huang, H. Ding, Z. Wang, S. D. Wilson, and V. Madhavan

Phys. Rev. Lett. 106, 206805-206808 (2011)

 

qsmu_pub3

Three energy- and temperature-scales corresponding to competing pseudogap state, incoherent-, and coherent-superconductivity in high-Tc cuprates

Y. Okada, T. Kawaguchi, M. Ohkawa, K. Ishizaka, T. Takeuchi, S. Shin, and H. Ikuta

Phys. Rev. B 83, 104502-104507 (2011).

 

qsmu_pub2

Enhancement of superconducting fluctuation under the coexistence of a competing pseudogap state in Bi2Sr2-xRxCuOy

Y. Okada, Y. Kuzuya, T. Kawaguchi, and H. Ikuta

Phys. Rev. B 81, 214520-214524 (2010).

 

qsmu_pub1

Origin of the anomalously strong influence of out-of-plane disorder on high-Tc superconductivity

Y. Okada, T. Takeuchi, T. Baba, S. Shin, and H. Ikuta

Journal of Phys. Soc. Japan 77, 074714-074717 (2008).