{"id":2304,"date":"2010-05-17T22:54:38","date_gmt":"2010-05-17T20:54:38","guid":{"rendered":"http:\/\/localhost\/azgad\/wordpress\/?p=2304"},"modified":"2010-05-17T22:54:38","modified_gmt":"2010-05-17T20:54:38","slug":"the-%e2%80%98hall%e2%80%99-mark-of-a-quantum-magnet","status":"publish","type":"post","link":"https:\/\/azgad.com\/?p=2304","title":{"rendered":"The \u2018Hall\u2019 mark of a quantum magnet"},"content":{"rendered":"

.
\nThe presence of exotic particles, called spinons, might now be detectable in a magnetic field, providing insight into quantum magnet properties<\/strong>
\n.
\nAn important model to explain high-temperature superconductivity is the
\nso-called \u2018quantum spin liquid\u2019. Scientists are therefore interested in
\nunderstanding the low-energy excitations of this magnetic state. Now,
\na theoretical study by a research team from RIKEN and the Massachusetts Institute
\n of Technology, USA, has explained how the properties of spin liquids could be
\n revealed by a simple heat-transfer experiment.
\n.
\n.<\/p>\n

In an insulating magnetic crystal, the electronic spins are localized to the atoms
\n that form the crystal lattice. For most such magnets, or antiferromagnets, the chemical
\nbonds favor an arrangement where, at low temperatures, each spin points in a direction
\nopposite to that of its neighbor. However, on a triangular lattice, such as the \u2018Kagome lattice\u2019,
\n.
\n a spin cannot simultaneously be opposite to all of its neighbors. The spins in these magnets
\n never order, even at very low temperatures\u2014giving rise to the name quantum spin liquid.
\n.<\/p>\n

\u201cSpin liquids have an exotic electronic state because [their] electrons can effectively
\ndissociate into distinguishable spin- and charge-carrying particles,\u201d explains team-member
\nNaoto Nagaosa from the RIKEN Advanced Science Institute, Wako. \u201cThe spin-carrying particle
\n is called a spinon and determines the low-energy properties of the magnet.\u201d
\n. <\/p>\n

To date, however, few experiments have found spinons. Nagaosa and his collaborators
\n explain how a method similar to the so-called \u2018Hall measurement\u2019\u2014an indispensible technique
\n for studying the properties of semiconductors\u2014could be used to detect spinons.
\n.<\/p>\n

In the classic version of the Hall measurement, a magnetic field is applied perpendicular
\n to a charge-carrying current, causing positive charges to curve one way and negative
\ncharges the other. The deflection of the charges provides information about their properties,
\n including their sign.
\n.<\/p>\n

In the \u2018thermal Hall effect\u2019 considered by Nagaosa and his colleagues, temperature serves
\n as the driving force to create a current\u2014not of charges, but of magnetic excitations\u2014that
\nflow in a magnetic field. For a spin liquid, these excitations are the spinons. As in the classic Hall
\n effect, a magnetic field will deflect these excitations, which will change the direction of the heat
\nflow\u2014an effect that experimentalists should be able to measure.
\n.<\/p>\n

Nagaosa and his colleagues showed that while there is no thermal Hall effect in most conventional
\nantiferromagnets, the presence of spinons in a spin liquid would result in a clear effect. This
\n experimental probe could therefore become an important way to identify and study excitations
\nof quantum magnets.
\n.<\/p>\n","protected":false},"excerpt":{"rendered":"

. The presence of exotic particles, called spinons, might now be detectable in a magnetic field, providing insight into quantum magnet properties . An important model to explain high-temperature superconductivity is the so-called \u2018quantum spin liquid\u2019. Scientists are therefore interested in understanding the low-energy excitations of this magnetic state. Now, a theoretical study by a … <\/p>\n

\u05d4\u05de\u05e9\u05d9\u05db\u05d5 \u05d1\u05e7\u05e8\u05d9\u05d0\u05d4<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[10],"tags":[513,49,260],"class_list":["post-2304","post","type-post","status-publish","format-standard","hentry","category-10","tag-513","tag-49","tag-260","nodate","item-wrap"],"_links":{"self":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/2304","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2304"}],"version-history":[{"count":1,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/2304\/revisions"}],"predecessor-version":[{"id":2305,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/2304\/revisions\/2305"}],"wp:attachment":[{"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2304"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2304"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}