How to avoid move constructor when I use implicit conversion in VS 11.0

First I defined a template overloading function(c:\git\feim\core\qpropertylist.hpp)

template<class T>
inline const T QPropertyList::get(const std::string& key, const T& defVal) const
{ 
    const_iterator it = find(key);
    if (it!=this->end())
    {


        it->second.setKey(key);  //To do : remove this
        return it->second;

    } else {
        return defVal;
    }
}

In the source file( c:\git\feim\core\capfloorleg.c(77) ), I begin to make this template instantiation

tenor2 = aPL.get("Tenor2", std::string(""));

Then I get the error as follows:

>c:\git\feim\core\qpropertylist.hpp(114): error C2668: 'std::basic_string<_Elem,_Traits,_Alloc>::basic_string' : ambiguous call to overloaded function
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>,
1>              _Alloc=std::allocator<char>
1>          ] (..\..\core\capFloorLeg.C)
1>          c:\program files (x86)\microsoft visual studio 11.0\vc\include\xstring(896): could be 'std::basic_string<_Elem,_Traits,_Alloc>::basic_string(std::basic_string<_Elem,_Traits,_Alloc> &&) throw()'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>,
1>              _Alloc=std::allocator<char>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 11.0\vc\include\xstring(789): or       'std::basic_string<_Elem,_Traits,_Alloc>::basic_string(const _Elem *)'
1>          with
1>          [
1>              _Elem=char,
1>              _Traits=std::char_traits<char>,
1>              _Alloc=std::allocator<char>
1>          ]
1>          while trying to match the argument list '(STC::QProperty)'
1>          c:\git\feim\core\capfloorleg.c(77) : see reference to function template instantiation 'const T STC::QPropertyList::get<std::basic_string<_Elem,_Traits,_Alloc>>(const std::string &,const T &) const' being compiled
1>          with
1>          [
1>              T=std::basic_string<char,std::char_traits<char>,std::allocator<char>>,
1>              _Elem=char,
1>              _Traits=std::char_traits<char>,
1>              _Alloc=std::allocator<char>
1>          ]

Error 2 error C2668: 'std::basic_string<_Elem,_Traits,_Alloc>::basic_string' : ambiguous call to overloaded function c:\git\feim\core\qpropertylist.hpp 111 1 core

I know this error is caused by the move constructor when I want to use implicit conversion (std::string(""))introduced by VS11.0, since in the VS8, everything is fine.

Anyone have a good idea how to avoid this error? Thanks a lot!!