First-principles investigation of transient spin transfer torque in magnetic multilayer systems

First-principles investigation of transient spin transfer torque in magnetic multilayer systems By employing the nonequilibrium Green's function (NEGF) method, the transient current and the transient behavior of the spin transfer torque (STT) of the magnetic layered system are investigated within the framework of density functional theory (DFT). To reduce the huge computational cost of the transient calculation, especially when the dense mesh of k sampling is present for layered systems, the complex absorbing potential (CAP) and the Padé spectrum decomposition are used so that the energy integrals in calculating transient current and STT can be performed analytically using residue theorem, which dramatically reduces the computational complexity of the first-principles calculation of transient behavior. As an application of the NEGF-DFT-CAP formalism, the transient current and current-induced STT of the Co/Cu/Co trilayer system are studied under an upward bias pulse for different angles of magnetization direction between two leads. The transient current shows a damped oscillatory behavior with the oscillation frequency proportional to the applied bias, leading to a relaxation time of hundreds of femtoseconds. The time-dependent STTs show roughly the same profile for systems with different rotating angles. The oscillation behavior is also observed as the transient STT approaches the steady state value. Such oscillations can be attributed to the interface resonant states. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Physical Review B American Physical Society (APS)

First-principles investigation of transient spin transfer torque in magnetic multilayer systems

Preview Only

First-principles investigation of transient spin transfer torque in magnetic multilayer systems

Abstract

By employing the nonequilibrium Green's function (NEGF) method, the transient current and the transient behavior of the spin transfer torque (STT) of the magnetic layered system are investigated within the framework of density functional theory (DFT). To reduce the huge computational cost of the transient calculation, especially when the dense mesh of k sampling is present for layered systems, the complex absorbing potential (CAP) and the Padé spectrum decomposition are used so that the energy integrals in calculating transient current and STT can be performed analytically using residue theorem, which dramatically reduces the computational complexity of the first-principles calculation of transient behavior. As an application of the NEGF-DFT-CAP formalism, the transient current and current-induced STT of the Co/Cu/Co trilayer system are studied under an upward bias pulse for different angles of magnetization direction between two leads. The transient current shows a damped oscillatory behavior with the oscillation frequency proportional to the applied bias, leading to a relaxation time of hundreds of femtoseconds. The time-dependent STTs show roughly the same profile for systems with different rotating angles. The oscillation behavior is also observed as the transient STT approaches the steady state value. Such oscillations can be attributed to the interface resonant states.
Loading next page...
 
/lp/aps_physical/first-principles-investigation-of-transient-spin-transfer-torque-in-H47ZnxOpqY
Publisher
The American Physical Society
Copyright
Copyright © ©2017 American Physical Society
ISSN
1098-0121
eISSN
1550-235X
D.O.I.
10.1103/PhysRevB.96.075412
Publisher site
See Article on Publisher Site

Abstract

By employing the nonequilibrium Green's function (NEGF) method, the transient current and the transient behavior of the spin transfer torque (STT) of the magnetic layered system are investigated within the framework of density functional theory (DFT). To reduce the huge computational cost of the transient calculation, especially when the dense mesh of k sampling is present for layered systems, the complex absorbing potential (CAP) and the Padé spectrum decomposition are used so that the energy integrals in calculating transient current and STT can be performed analytically using residue theorem, which dramatically reduces the computational complexity of the first-principles calculation of transient behavior. As an application of the NEGF-DFT-CAP formalism, the transient current and current-induced STT of the Co/Cu/Co trilayer system are studied under an upward bias pulse for different angles of magnetization direction between two leads. The transient current shows a damped oscillatory behavior with the oscillation frequency proportional to the applied bias, leading to a relaxation time of hundreds of femtoseconds. The time-dependent STTs show roughly the same profile for systems with different rotating angles. The oscillation behavior is also observed as the transient STT approaches the steady state value. Such oscillations can be attributed to the interface resonant states.

Journal

Physical Review BAmerican Physical Society (APS)

Published: Aug 9, 2017

There are no references for this article.

Sorry, we don’t have permission to share this article on DeepDyve,
but here are related articles that you can start reading right now:

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off