專題演講

2018/09/20(Thu)     10:30 -12:00    5th Floor(1st meeting room)

Title

Advanced scanning tunneling microscopy techniques for condensed matter researches: spin- and orbital-resolved STM

Speaker

Prof. Yasuo Yoshida

Department of Physics, Kanazawa University, Japan

Abstract

Since the invention of scanning tunneling microscopy (STM), scanning probe microscopy techniques have been developed in many different directions in the last 40 years. Spin-polarized STM is one of the cutting edges and highly appreciated for condensed matter researches [1]. The spin sensitivity is down to the atomic scale and new techniques have been reported combining the spin sensitivity with other techniques like atomic manipulation, microwave, and pump-probe method. In addition to spin sensitivity with spin-polarized STM, we recently proved that STM can access atomic orbitals by precisely controlling the tunneling gap. In my talk, I will present experiments that demonstrate such capabilities of STM and new phenomena which were previously inaccessible. Spin-resolved STM visualized not only spin structures of chiral magnets [2, 3] but also spin-selective orbital shapes of Co atoms on chiral magnetic templates [4, 5]. Orbital-resolved STM revealed the emergence of surface-assisted orbital ordering in a heavily-investigated heavy fermion superconductor [6]. Prospects of future researches with spin- and orbital-resolved STM will be discussed at the end of the talk if time allows.

References

[1] R. Wiesendanger, Rev. Mod. Phys. 81, 1495 (2009).
[2] M. Bode et al., Nature 447, 190 (2007)
[3] Y. Yoshida et al., Phys. Rev. Lett. 108, 087205 (2012).
[4] D. Serrate, P. Ferriani, Y. Yoshida, et al., Nat. Nanotech. 5, 350-353 (2010).
[5] D. Serrate, Y. Yoshida, et al., Phys. Rev. B 93, 125424 (2016)
.
[6] H. Kim, Y. Yoshida, et al., Sci. Adv. 3, eaao0362 (2017).