ࡱ> :<9Y Rbjbj2pepe   aaaaauuu8u p          $ #%A a     A aa4V 999 vaa 9  999 [Hz9 l 0 9&^&99&&a_  9     A A @       &           ': Ultrafast optical studies of valley states in 2D transition metal dichalcogenides Jonghwan Kim Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 Abstract: The valley degree of freedom in 2D transition metal dichalcogenides (TMD) recently emerged as a novel information carrier in addition to spin and charge. The valley electronic states are shown to be easily accessible via circular polarization of photoexcitation. In addition, the intrinsic valley lifetime is expected to be remarkably long due to the unique spin-valley locking behavior. Here, we report efficient generation of microsecond-long lived valley polarization via ultrafast charge transfer process in WSe2/MoS2 heterostructures. This valley polarization has near unity degree and several orders of magnitude longer lifetime than previously reported values. Our ultrafast optical studies reveal promising potential of valley electronic states in TMD heterostructures for novel valleytronics and spintronics applications. Short Biography: Jonghwan Kim, Ph. D., is interested in novel quantum phenomena emerging in low-dimension nanomaterials for fascinating optical science and optoelectronics. He has obtained Ph.D. in Physics at UC Berkeley in 2015 with the focus on ultrafast optical spectroscopy/microscopy, high quality 2D material preparation and nano-device fabrication. In POSTECH, as an assistant professor started from 2017, he has been constructing an interdisciplinary research team at the department of materials science and engineering to connect the bridge between fundamental physics and advanced material engineering.      QRS_`aueL8$&hVDhJ5CJOJPJ\nHtH&hVDhJG5CJOJPJ\nHtH0hVDhc@>*B*CJOJPJaJnHphtHhrh>eUCJOJPJ\aJhrCJOJaJ6hVDhx16B*CJH*OJPJ]aJnHphtH%h>eUh>eUB*CJOJPJaJph"hVDhVD5CJOJPJ\aJ+hVDhx15CJ KHOJPJaJ mH sH +h>eUh>eU5CJ KHOJPJaJ mH sH %h>eU5CJ KHOJPJaJ mH sH  RS`a       ! gdJG d4$G$gdc@ dx4$G$gd $d4$a$gdc@$d4$G$^a$gd>eU $d4$G$a$gd>eU $d4$G$a$gdc@  ! 0 1 2  ÷{{h`\`\`\`\hhQ jhQ U$hVDhJCJOJPJaJnHtHhCJOJPJnHtH hhCJOJPJnHtH hVDhJCJOJPJnHtHhVDhJ5CJOJhVDhVD5CJOJhVDhVDCJOJhrCJOJhrCJOJo(h>eUh>eUCJOJhVDh7oCJOJhVDhCJOJ d4$G$gdc@gdJG01h2P. A!"#$% w2 0@P`p2( 0@P`p 0@P`p 0@P`p 0@P`p 0@P`p 0@P`p8XV~ 0@ 0@ 0@ 0@ 0@ 0@ 0@ 0@ 0@ 0@ 0@ 0@ 0@ 0@6666PJ_HmH nHsH tHR`R x1\$1$4$7$8$a$ KHOJ_HaJmH nHsH tH(A ( 0 } 4BiB \ \4 l4a $k $] L `` x1Preprint Heading1$4$7$8$5CJKHOJaJtH ^^ x1 Preprint Bodyh1$4$7$8$`hCJKHOJaJtH 0^0 W;| ()CJOJ.U !. / #Xt|l >*B*phfA2f 7oP1_title$1$4$7$8$a$5KHOJPJQJ^JnHtH.ZB. 7o̹ QJ^JaJPRP JG8'$ 9r &dG$Pa$CJaJ@/a@ JG8 CharCJKHOJaJnHtH> r> JG$ 9r G$a$CJaJ@/@ JG CharCJKHOJaJnHtH2/2 V0@NB*ph+Wq PK![Content_Types].xmlN0EH-J@%ǎǢ|ș$زULTB l,3;rØJB+$G]7O٭VR.e1a$nN9 ʣsЛrRiDRKQjdٿ>0E*R>V%ӪBS!a;(o,\=Hr촦f Fw_ ưѧh:f\lZ?ȱ({t47w8wCvQh5(Ç; l;f;~ )IOwЕQW=ta0jr a]j9KXKGP@$I=Z9BS?_LpVU_}=02/`"vOL9YȎ?xӋzg/;"Q,3U!J#S檧 _V+L_˿`ĄOHw{Y t'rSFH?B9p=l1T^>cġnXchq 3Oi䞜/MC\sQjyy\@%.[4PJKO}N1vcB,)gͥ1z8M2!'V4B$\ߖm{=F]3 {Q oDK%4xŧ&n($x:”y%sz Eݜn?FrIN]:c&rN1J.오PB".1wz?tld9R %w6fVWt+tyb.'-#+00}`c ;1dC ;ȎUb=#"sJ<+&|n|xa3:yNOM=M ċ(0{1 zx]qc/X4./A_Z)FL&(fwJ bQU-rs{njz^ q+R%})pهm 2}溳;|:~&?by7L@w=}=JrE?~F0'ޜ.bxTe&pGZL~Dd<ΈR\u$pt.c6ˎn]P!aLf;H4׃Hp WNX,ZJU;,+ۃ? @TZSw3ߥӊhPx]Z]jE7nD ?TqY_ Z)|ZfM,k 453Mߨ2Ss8:d#//D#JmdrD\',$DbQt|hsVABxoɵ!o鶓|t1,Br[-~udKp8{'t"YU7̚3WbDVVaӮy'c(Gt    @ @H 0(  0(  B S  ?S[2:lpvS_vRS_` !?`H7[R$#Bsq$ApyKAOro\ , i  j3 g A  j( } D4 6|SM 1Up a W=z}i=K8,h'(3"7| / #J$p$J%%C&'&V'.(M(z&)O*q,7t,r/z/O0d396$ 7;H7I7:\7w8W;.<s<u7=7R=a=Z@>°>>?.?c,RMnJ!.ᰭWeUVV6JVjdWX-YsF\(_\C_K`Xx`$a'a$0bBbVczewdgFh]NjZj_ujkck.muDn7oWopprp-t[v4wExxe1y+zB{8|oC|"j|*}U~F['9-a z|L"]+d} [hMq[ nRTJ7j!Z^k vt?UUx1 j ":Uu*~ j7[QjeWp//X[2n(]O"Hhhxz?(Ic_/N}J^xkZSDQzY#&F} :s+|S~0cH ?^ fK,MXmbeA^g o_Cn5gQx^(dtE}!l3Q M"9n}7P 1ZieZqU=GE2[hjs@@Unknown G.[x Times New Roman5Symbol3. .[x Arial3> /|)ѹ@ O=  jMS MinchoMS Mincho;  1UAAA?;(SimSun[SO;|i0Batang?= .Cx Courier NewA$BCambria Math q hXck'   !"!%),.:;?]}  2 3 ! 0 0 0000 =]([\{  0 0 0000;[r 3qHP ?x12! xx[=N fORGANIC MATERILAS FOR ELECTRONICS AND PHOTONICS (Title: Times New Roman, 14 pt, bold, capital letters)tйJKIM Oh+'0 (8 HT t  hORGANIC MATERILAS FOR ELECTRONICS AND PHOTONICS (Title: Times New Roman, 14 pt, bold, capital letters)ýNormalJKIM6Microsoft Office Word@vA@`D"@*VHz ՜.+,0X hp  ;Ɽ  gORGANIC MATERILAS FOR ELECTRONICS AND PHOTONICS (Title: Times New Roman, 14 pt, bold, capital letters)   !"#$%&'(*+,-./02345678;Root Entry Fp}[Hz=Data  1Table&WordDocument2SummaryInformation()DocumentSummaryInformation81CompObjn  FMicrosoft Word 97-2003 MSWordDocWord.Document.89q