TY - JOUR
T1 - High magnetoresistance of a hexagonal boron nitride-graphene heterostructure-based MTJ through excited-electron transmission
AU - Harfah, Halimah
AU - Wicaksono, Yusuf
AU - Sunnardianto, Gagus Ketut
AU - Majidi, Muhammad Aziz
AU - Kusakabe, Koichi
N1 - Funding Information:
The calculations were performed at the computer centers of Kyushu University. This work was partly supported by JSPS KAKENHI Grant No. JP19H00862 and JP16H00914 in Science of Atomic Layers, 21J22520 and 20J22909 in Grants-in-aid for Young Scientists, and JP18K03456. Y. W. gratefully acknowledges fellowship support from the Japan Society for the Promotion of Science (JSPS). H. H. gratefully acknowledges fellowship support from JSPS and scholarship support from the Japan International Cooperation Agency (JICA) within the “Innovative Asia” Program, ID Number D1805252. G. K. S. and M. A. M. acknowledge the JSPS International Fellowship with numbers L21547 and S21113, respectively.
Funding Information:
The calculations were performed at the computer centers of Kyushu University. This work was partly supported by JSPS KAKENHI Grant No. JP19H00862 and JP16H00914 in Science of Atomic Layers, 21J22520 and 20J22909 in Grants-in-aid for Young Scientists, and JP18K03456. Y. W. gratefully acknowledges fellowship support from the Japan Society for the Promotion of Science (JSPS). H. H. gratefully acknowledges fellowship support from JSPS and scholarship support from the Japan International Cooperation Agency (JICA) within the ?Innovative Asia? Program, ID Number D1805252. G. K. S. and M. A. M. acknowledge the JSPS International Fellowship with numbers L21547 and S21113, respectively.
Publisher Copyright:
© The Royal Society of Chemistry 2021.
PY - 2022/1/7
Y1 - 2022/1/7
N2 - This work presents anab initiostudy of a few-layer hexagonal boron nitride (hBN) and hBN-graphene heterostructure sandwiched between Ni(111) layers. The aim of this study is to understand the electron transmission process through the interface. Spin-polarized density functional theory calculations and transmission probability calculations were conducted on Ni(111)/nhBN/Ni(111) withn= 2, 3, 4, and 5 as well as on Ni(111)/hBN-Gr-hBN/Ni(111). Slabs with magnetic alignment in an anti-parallel configuration (APC) and parallel configuration (PC) were considered. The pd-hybridizations at both the upper and lower interfaces between the Ni slabs and hBN were found to stabilize the system. The Ni/nhBN/Ni magnetic tunnel junction (MTJ) was found to exhibit a high tunneling magnetoresistance (TMR) ratio at ∼0.28 eV forn= 2 and 0.34 eV forn> 2, which are slightly higher than the Fermi energy. The observed shifting of this high TMR ratio originates from the transmission of electrons through the surface states of the dz2-orbital of Ni atoms at interfaces which are hybridized with the pz-orbital of N atoms. In the case ofn> 2, the proximity effect causes an evanescent wave, contributing to decreasing transmission probability but increasing the TMR ratio. However, the TMR ratio, as well as transmission probability, was found to be increased upon replacing the unhybridized hBN layer of the Ni/3hBN/Ni MTJ with graphene, thus yielding Ni/hBN-Gr-hBN/Ni. A TMR ratio as high as ∼1200% was observed at an energy of 0.34 eV, which is higher than the Fermi energy. Furthermore, a design is proposed for a device based on a new reading mechanism using the high TMR ratio observed just above the Fermi energy level.
AB - This work presents anab initiostudy of a few-layer hexagonal boron nitride (hBN) and hBN-graphene heterostructure sandwiched between Ni(111) layers. The aim of this study is to understand the electron transmission process through the interface. Spin-polarized density functional theory calculations and transmission probability calculations were conducted on Ni(111)/nhBN/Ni(111) withn= 2, 3, 4, and 5 as well as on Ni(111)/hBN-Gr-hBN/Ni(111). Slabs with magnetic alignment in an anti-parallel configuration (APC) and parallel configuration (PC) were considered. The pd-hybridizations at both the upper and lower interfaces between the Ni slabs and hBN were found to stabilize the system. The Ni/nhBN/Ni magnetic tunnel junction (MTJ) was found to exhibit a high tunneling magnetoresistance (TMR) ratio at ∼0.28 eV forn= 2 and 0.34 eV forn> 2, which are slightly higher than the Fermi energy. The observed shifting of this high TMR ratio originates from the transmission of electrons through the surface states of the dz2-orbital of Ni atoms at interfaces which are hybridized with the pz-orbital of N atoms. In the case ofn> 2, the proximity effect causes an evanescent wave, contributing to decreasing transmission probability but increasing the TMR ratio. However, the TMR ratio, as well as transmission probability, was found to be increased upon replacing the unhybridized hBN layer of the Ni/3hBN/Ni MTJ with graphene, thus yielding Ni/hBN-Gr-hBN/Ni. A TMR ratio as high as ∼1200% was observed at an energy of 0.34 eV, which is higher than the Fermi energy. Furthermore, a design is proposed for a device based on a new reading mechanism using the high TMR ratio observed just above the Fermi energy level.
UR - http://www.scopus.com/inward/record.url?scp=85121710778&partnerID=8YFLogxK
U2 - 10.1039/d1na00272d
DO - 10.1039/d1na00272d
M3 - Article
AN - SCOPUS:85121710778
SN - 2516-0230
VL - 4
SP - 117
EP - 124
JO - Nanoscale Advances
JF - Nanoscale Advances
IS - 1
ER -