Title: The phase transition in VO₂ probed using x-ray, visible and infrared radiations

Abstract

Vanadium dioxide (VO₂) is a model system that has been used to understand closely occurring multiband electronic (Mott) and structural (Peierls) transitions for over half a century due to continued scientific and technological interests. Among the many techniques used to study VO₂, the most frequently used involve electromagnetic radiation as a probe. Understanding of the distinct physical information provided by different probing radiations is incomplete, mostly owing to the complicated nature of the phase transitions. Here, we use transmission of spatially averaged infrared (λ = 1.5 μm) and visible (λ = 500 nm) radiations followed by spectroscopy and nanoscale imaging using x-rays (λ = 2.25–2.38 nm) to probe the same VO₂ sample while controlling the ambient temperature across its hysteretic phase transitions and monitoring its electrical resistance. We directly observed nanoscale puddles of distinct electronic and structural compositions during the transition. The two main results are that, during both heating and cooling, the transition of infrared and visible transmission occurs at significantly lower temperatures than the Mott transition, and the electronic (Mott) transition occurs before the structural (Peierls) transition in temperature. We use our data to provide insights into possible microphysical origins of the different transition characteristics. We highlight thatmore » it is important to understand these effects because small changes in the nature of the probe can yield quantitatively, and even qualitatively, different results when applied to a non-trivial multiband phase transition. Our results guide more judicious use of probe type and interpretation of the resulting data.« less

Authors:

Kumar, Suhas  ^[1];

• Search DOE PAGES for author "Kumar, Suhas"
• Search DOE PAGES for ORCID "0000-0002-6772-7250"

Strachan, John Paul ^[1]; Kilcoyne, A. L. David ^[2]; Tyliszczak, Tolek ^[2]; Pickett, Matthew D. ^[1]; Santori, Charles ^[1]; Gibson, Gary  ^[1];

• Search DOE PAGES for author "Gibson, Gary"
• Search DOE PAGES for ORCID "0000-0002-7139-9245"

Williams, R. Stanley ^[1]

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+ Show Author Affiliations

1. Hewlett Packard Labs., Palo Alto, CA (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Publication Date:

Mon Feb 15 00:00:00 EST 2016

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1393028

Alternate Identifier(s):

OSTI ID: 1238077

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Applied Physics Letters

Additional Journal Information:

Journal Volume: 108; Journal Issue: 7; Journal ID: ISSN 0003-6951

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE