P09S

22AU002

BL-1 (HiSOR)

Strain-Induced Relocation of Topological Surface States in
Bi2Se3 Single Crystal
Y. Kumara, S. Kumarb, S. Idetaa,b, T. Okudaa,b, K. Shimadaa,ba

Graduate School of Advanced Science and Engineering, Hiroshima University, Japan 739-0046
bHiroshima Synchrotron Radiation Centre (HiSOR), Hiroshima University, Japan 739-0046

Keywords: Topological Insulator, in-situ Strain, ARPES, Dirac point, Straintronics.

To investigate the impact of strain on the surface and bulk electronic states of solids, we havedeveloped a new sample holder for in-situ strain application for ARPES experiments at low temperatures. In
this study, we report the design of the sample holder and ARPES results of a strain-induced modification of
the surface and bulk states of Bi2Se3 single crystal. Our findings reveal significant alterations in the electronic
band structure [6] (in terms of energy and momentum) of the Bi2Se3 layered topological insulator [1-4] whensubjected to tensile strain. Specifically, tensile strain leads to a closer proximity of the Dirac point (DP) tothe Fermi level (lower binding energy), while compressive strain results in the DP moving further away fromthe Fermi level (higher binding energy). This study demonstrates the tunability of both surface and bulk
electronic states in Bi2Se3 through the in-situ application of strain and underscores the potential of strainengineering for “Straintronics” [5] devices. The sample holder developed for this purpose holds promise foradvancing research on the electronic band structures of layered materials, including topological insulatorsand quantum materials [6-8], under strain conditions.
No Strain

TS_1R

TS_2R

RNP

TS_3R

̅ for Bi2Se3 single crystal with increasing tensile strain (TS) from TS_1R, to TS_2R,
FIGURE 1. ARPES maps along Г̅ − 𝐾
to TS_3R measured at 10 K with 25 eV photon energy. The DP moves to the lower energy. The DP position was not recovered
to the original position though we remove the tensile strain (RNP).
TABLE 1. Changes in fermi velocity, bottom of conduction band and shift in dirac point with respact to applied starin.
Change in parameters

𝑵𝒐 𝑺𝒕𝒓𝒂𝒊𝒏

𝑻𝑺_𝟏𝑹

𝑻𝑺_𝟐𝑹

𝑻𝑺_𝟑𝑹

𝑹𝑵𝑷

𝒌𝑭 (Å−𝟏 )0.08480.08460.08760.10370.1080𝑩𝒐𝒕𝒕𝒐𝒎 𝒐𝒇 𝒄𝒐𝒏𝒅𝒖𝒄𝒕𝒊𝒐𝒏 𝒃𝒂𝒏𝒅 (𝒆𝑽)−0.1555−0.1605−0.1655−0.1806−0.1856

𝑫𝒊𝒓𝒂𝒄 𝑷𝒐𝒊𝒏𝒕 (𝒆𝑽)−0.3398−0.3520−0.3584−0.3729−0.3862

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